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Methicillin-resistant Staphylococcus aureus (MRSA) is an important zoonotic pathogen associated with a wide range of infections in humans and animals. Thus, the emergence of MRSA clones poses an important threat to human and animal health. This study is aimed at elucidating the genomics insights of a strong biofilm-producing and multidrug-resistant (MDR) S. aureus MTR_BAU_H1 strain through whole-genome sequencing (WGS). The S. aureus MTR_BAU_H1 strain was isolated from food handlers hand swabs in Bangladesh and phenotypically assessed for antimicrobial susceptibility and biofilm production assays. The isolate was further undergone to high throughput WGS and analysed using different bioinformatics tools to elucidate the genetic diversity, molecular epidemiology, sequence type (ST), antimicrobial resistance, and virulence gene distribution. Phenotypic analyses revealed that the S. aureus MTR_BAU_H1 strain is a strong biofilm-former and carries both antimicrobial resistance (e.g., methicillin resistance; mecA, beta-lactam resistance; blaZ and tetracycline resistance; tetC) and virulence (e.g., sea, tsst, and PVL) genes. The genome of the S. aureus MTR_BAU_H1 belonged to ST1930 that possessed three plasmid replicons (e.g., rep16, rep7c, and rep19), seven prophages, and two clustered regularly interspaced short palindromic repeat (CRISPR) arrays of varying sizes. Phylogenetic analysis showed a close evolutionary relationship between the MTR_BAU_H1 genome and other MRSA clones of diverse hosts and demographics. The MTR_BAU_H1 genome harbours 42 antimicrobial resistance genes (ARGs), 128 virulence genes, and 273 SEED subsystems coding for the metabolism of amino acids, carbohydrates, proteins, cofactors, vitamins, minerals, and lipids. This is the first-ever WGS-based study of a strong biofilm-producing and MDR S. aureus strain isolated from human hand swabs in Bangladesh that unveils new information on the resistomes (ARGs and correlated mechanisms) and virulence potentials that might be linked to staphylococcal pathogenesis in both humans and animals.

BACKGROUND AND OBJECTIVES: The utilization of disposable masks during and subsequent to the COVID-19 pandemic has led to the emergence of mask waste. The bacteria that thrive on mask waste have special characteristics. The objective of this research was to identify, choose, and analyze the bacteria present in discarded face masks at landfill sites (Piyungan, Yogyakarta and Jatibarang, Semarang), coastal areas (Tanjung Pasir, Tangerang, and Marina, Semarang), as well as mangrove forests (Teluk Naga, Tangerang, and Tirang, Semarang) situated in Java, Indonesia. METHODS: The bacterial isolation was performed using minimal salt medium. Bacterial isolates were screened in a minimal salt medium supplemented with three types of masks (black duckbill, blue medical, white Korean filter) as the sole carbon and energy source at the various potential of hydrogen levels (5, 7, 9), temperatures (10, 30, 50 degrees Celsius), and sodium chloride concentrations (2.5, 5.0, 7.5 percent). The bacterial strains with the highest optical density values across all treatments were determined through the sequencing of the 16S ribosomal ribonucleic acid gene. These selected bacteria were then evaluated for their ability to produce biofilms under different potential of hydrogen and salt concentrations. The resistance to heavy metals (lead, copper, iron) and antibiotics (penicillin, chloramphenicol, tetracycline, erythromycin, ciprofloxacin, kanamycin) was also investigated. FINDINGS: A grand total of 183 bacterial strains were obtained, comprising 80 isolates from landfills, 47 isolates from beaches, and 56 isolates from mangroves. The selected bacteria identified as Bacillus cereus, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus sciuri, and Staphylococcus arlettae based on 16 svedberg ribosomal ribonucleic acid gene analysis. The chosen strains exhibited the capacity to generate biofilm across various potential of hydrogen and salinity conditions. Furthermore, these strains displayed resilience to heavy metals (such as lead, copper, and iron) as well as resistance to antibiotics (including penicillin, chloramphenicol, tetracycline, erythromycin, ciprofloxacin, and kanamycin). CONCLUSION: Mask waste discovered in landfills, beaches, and mangroves can promote bacterial growth. This study indicated that the selected bacteria are capable of flourishing through the utilization of various mask types as their exclusive carbon and energy source across a wide range of potential of hydrogen levels, temperatures, and salinity concentrations. The ability to produce biofilms, withstand antibiotics, and endure heavy metal ions provides a protective environment for bacteria, enhancing their resilience against environmental stresses, and antimicrobial agents. Analysis of bacterial profiles reveals the intricate connections between microorganisms and their surroundings. The results of this study have implications for public health, environmental pollution, and ecosystem dynamics. [ABSTRACT FROM AUTHOR]

The majority of tympanoplasty surgeons recommend air-conduction hearing aids to patients who have residual hearing loss. The present study aimed to use silico stimulation against gram positive and negative bacteria isolated from hearing aids that produce biofilm formations. More than 150 patients (hearing aid users), including both sexes, were surveyed to gather samples for the study of hearing aids. From September to December 2023, the samples were collected from Ramadi Teaching Hospital and Ramadi Children and Maternity Hospital in Ramadi, Iraq. There was a 64/53.3% increase in the prevalence of harmful microorganisms in men compared to females who used hearing aids. Most infected individuals were 70 and older (25/20.8%). The microtitration plate method was used to determine the biofilm formation ability of the isolates. The findings showed that 15% of Staphylococcus aureus isolates formed strong biofilms, 5.8% of the isolates of Psuedomonas. aeruginosa formed strong biofilms, and only 1% of the isolates of Stapylococcus. epidermidis, Escherichia coli, Proteus mirabilis and Klebsiella pneumonia formed strong biofilms. There is a According to the latest research, the risk of microbial infection in those who use hearing aids increases over time. When different protein-drug docking analyses were done, different species (P. mirabilis, Ps aeruginosa, Staphylococcus aureus, and Streptococcus pneumonia) had different binding affinities. The molecular docking analysis of all the proteins with the selected drug compounds resulted in varied binding affinities for all the species (P. mirabilis, Ps. aeruginosa, S. aureus, and St. pneumoniae). The binding affinities for all species resulted in the range from -13.52 kcal/mol (aliBCefilavancin complex) to -2.72 kcal/mol (fib-Disulfiram complex). The ear canal's microbiota changes when a hearing aid (HA) is worn. It raises the risk of otitis externa by promoting the growth of pathogenic bacteria. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: The utilization of disposable masks during and subsequent to the COVID-19 pandemic has led to the emergence of mask waste. The bacteria that thrive on mask waste have special characteristics. The objective of this research was to identify, choose, and analyze the bacteria present in discarded face masks at landfill sites (Piyungan, Yogyakarta and Jatibarang, Semarang), coastal areas (Tanjung Pasir, Tangerang, and Marina, Semarang), as well as mangrove forests (Teluk Naga, Tangerang, and Tirang, Semarang) situated in Java, Indonesia.METHODS: The bacterial isolation was performed using minimal salt medium. Bacterial isolates were screened in a minimal salt medium supplemented with three types of masks (black duckbill, blue medical, white Korean filter) as the sole carbon and energy source at the various potential of hydrogen levels (5, 7, 9), temperatures (10, 30, 50 degrees Celsius), and sodium chloride concentrations (2.5, 5.0, 7.5 percent). The bacterial strains with the highest optical density values across all treatments were determined through the sequencing of the 16S ribosomal ribonucleic acid gene. These selected bacteria were then evaluated for their ability to produce biofilms under different potential of hydrogen and salt concentrations. The resistance to heavy metals (lead, copper, iron) and antibiotics (penicillin, chloramphenicol, tetracycline, erythromycin, ciprofloxacin, kanamycin) was also investigated.FINDINGS: A grand total of 183 bacterial strains were obtained, comprising 80 isolates from landfills, 47 isolates from beaches, and 56 isolates from mangroves. The selected bacteria identified as Bacillus cereus, Pseudomonas aeruginosa, Proteus mirabilis, Staphylococcus sciuri, and Staphylococcus arlettae based on 16 svedberg ribosomal ribonucleic acid gene analysis. The chosen strains exhibited the capacity to generate biofilm across various potential of hydrogen and salinity conditions. Furthermore, these strains displayed resilience to heavy metals (such as lead, copper, and iron) as well as resistance to antibiotics (including penicillin, chloramphenicol, tetracycline, erythromycin, ciprofloxacin, and kanamycin).CONCLUSION: Mask waste discovered in landfills, beaches, and mangroves can promote bacterial growth. This study indicated that the selected bacteria are capable of flourishing through the utilization of various mask types as their exclusive carbon and energy source across a wide range of potential of hydrogen levels, temperatures, and salinity concentrations. The ability to produce biofilms, withstand antibiotics, and endure heavy metal ions provides a protective environment for bacteria, enhancing their resilience against environmental stresses, and antimicrobial agents. Analysis of bacterial profiles reveals the intricate connections between microorganisms and their surroundings. The results of this study have implications for public health, environmental pollution, and ecosystem dynamics.

Methicillin‐resistant Staphylococcus aureus (MRSA) is an important zoonotic pathogen associated with a wide range of infections in humans and animals. Thus, the emergence of MRSA clones poses an important threat to human and animal health. This study is aimed at elucidating the genomics insights of a strong biofilm‐producing and multidrug‐resistant (MDR) S. aureus MTR_BAU_H1 strain through whole‐genome sequencing (WGS). The S. aureus MTR_BAU_H1 strain was isolated from food handlers' hand swabs in Bangladesh and phenotypically assessed for antimicrobial susceptibility and biofilm production assays. The isolate was further undergone to high throughput WGS and analysed using different bioinformatics tools to elucidate the genetic diversity, molecular epidemiology, sequence type (ST), antimicrobial resistance, and virulence gene distribution. Phenotypic analyses revealed that the S. aureus MTR_BAU_H1 strain is a strong biofilm‐former and carries both antimicrobial resistance (e.g., methicillin resistance; mecA, beta‐lactam resistance; blaZ and tetracycline resistance; tetC) and virulence (e.g., sea, tsst, and PVL) genes. The genome of the S. aureus MTR_BAU_H1 belonged to ST1930 that possessed three plasmid replicons (e.g., rep16, rep7c, and rep19), seven prophages, and two clustered regularly interspaced short palindromic repeat (CRISPR) arrays of varying sizes. Phylogenetic analysis showed a close evolutionary relationship between the MTR_BAU_H1 genome and other MRSA clones of diverse hosts and demographics. The MTR_BAU_H1 genome harbours 42 antimicrobial resistance genes (ARGs), 128 virulence genes, and 273 SEED subsystems coding for the metabolism of amino acids, carbohydrates, proteins, cofactors, vitamins, minerals, and lipids. This is the first‐ever WGS‐based study of a strong biofilm‐producing and MDR S. aureus strain isolated from human hand swabs in Bangladesh that unveils new information on the resistomes (ARGs and correlated mechanisms) and virulence potentials that might be linked to staphylococcal pathogenesis in both humans and animals. [ABSTRACT FROM AUTHOR]

In this study, rhizosphere and endophytic bacteria of kale (Brassica oleracea L. var. acephala) cultivars 'Winterbor' and 'Black Magic' were isolated and their efficacy to suppress damping-off of cabbage caused by Pythium aphanidermatum was evaluated. On nutrient agar medium, 10 bacterial isolates with different morphological characteristics were isolated from kale roots and rhizosphere soil. In an in vitro dual culture assay, two rhizosphere bacterial isolates (KRB1 and KRB2) obtained from 'Winterbor' exhibited high levels of inhibitory activity against the mycelial growth of P. aphanidermatum. Based on 16S rDNA sequence analysis, these bacterial isolates were identified as Pseudomonas alcaligenes (KRB1) and Rheinheimera mangrovi (KRB2). Soil application of P. alcaligenes KRB1 and R. mangrovi KRB2 reduced the damping-off incidence in cabbage by 42.4% and 45.5%, respectively compared to the infected control under controlled pot culture conditions. Both bacterial strains demonstrated the ability to form biofilm; however, P. alcaligenes KRB1 produced five times more biofilm than R. mangrovi KRB2. These bacterial strains produced volatile compounds that suppressed P. aphanidermatum growth in an in vitro assay. Gas chromatography-mass spectrometry analysis of volatile compounds revealed that P. alcaligenes KRB1 and R. mangrovi KRB2 predominantly produced L-alanine ethylamide, (S)-, accounting for 35.9% and 29.5% of the peak area, respectively. The capability to form biofilms and release anti-oomycete volatile compounds likely contributes to the biocontrol effectiveness of these bacterial strains against P. aphanidermatum. [ABSTRACT FROM AUTHOR]

Abstract Background Staphylococcus aureus is a notorious multidrug resistant pathogen prevalent in healthcare facilities worldwide. Unveiling the mechanisms underlying biofilm formation, quorum sensing and antibiotic resistance can help in developing more effective therapy for S. aureus infection. There is a scarcity of literature addressing the genetic profiles and correlations of biofilm-associated genes, quorum sensing, and antibiotic resistance among S. aureus isolates from Malaysia. Methods Biofilm and slime production of 68 methicillin-susceptible S. aureus (MSSA) and 54 methicillin-resistant (MRSA) isolates were determined using a a plate-based crystal violet assay and Congo Red agar method, respectively. The minimum inhibitory concentration values against 14 antibiotics were determined using VITEK® AST-GP67 cards and interpreted according to CLSI-M100 guidelines. Genetic profiling of 11 S. aureus biofilm-associated genes and agr/sar quorum sensing genes was performed using single or multiplex polymerase chain reaction (PCR) assays. Results In this study, 75.9% (n = 41) of MRSA and 83.8% (n = 57) of MSSA isolates showed strong biofilm-forming capabilities. Intermediate slime production was detected in approximately 70% of the isolates. Compared to MSSA, significantly higher resistance of clindamycin, erythromycin, and fluoroquinolones was noted among the MRSA isolates. The presence of intracellular adhesion A (icaA) gene was detected in all S. aureus isolates. All MSSA isolates harbored the laminin-binding protein (eno) gene, while all MRSA isolates harbored intracellular adhesion D (icaD), clumping factors A and B (clfA and clfB) genes. The presence of agrI and elastin-binding protein (ebpS) genes was significantly associated with biofilm production in MSSA and MRSA isolates, respectively. In addition, agrI gene was also significantly correlated with oxacillin, cefoxitin, and fluoroquinolone resistance. Conclusions The high prevalence of biofilm and slime production among MSSA and MRSA isolates correlates well with the detection of a high prevalence of biofilm-associated genes and agr quorum sensing system. A significant association of agrI gene was found with cefoxitin, oxacillin, and fluoroquinolone resistance. A more focused approach targeting biofilm-associated and quorum sensing genes is important in developing new surveillance and treatment strategies against S. aureus biofilm infection.

Background: Staphylococcus aureus is a notorious multidrug resistant pathogen prevalent in healthcare facilities worldwide. Unveiling the mechanisms underlying biofilm formation, quorum sensing and antibiotic resistance can help in developing more effective therapy for S. aureus infection. There is a scarcity of literature addressing the genetic profiles and correlations of biofilm-associated genes, quorum sensing, and antibiotic resistance among S. aureus isolates from Malaysia. Methods: Biofilm and slime production of 68 methicillin-susceptible S. aureus (MSSA) and 54 methicillin-resistant (MRSA) isolates were determined using a a plate-based crystal violet assay and Congo Red agar method, respectively. The minimum inhibitory concentration values against 14 antibiotics were determined using VITEK® AST-GP67 cards and interpreted according to CLSI-M100 guidelines. Genetic profiling of 11 S. aureus biofilm-associated genes and agr/sar quorum sensing genes was performed using single or multiplex polymerase chain reaction (PCR) assays. Results: In this study, 75.9% (n = 41) of MRSA and 83.8% (n = 57) of MSSA isolates showed strong biofilm-forming capabilities. Intermediate slime production was detected in approximately 70% of the isolates. Compared to MSSA, significantly higher resistance of clindamycin, erythromycin, and fluoroquinolones was noted among the MRSA isolates. The presence of intracellular adhesion A (icaA) gene was detected in all S. aureus isolates. All MSSA isolates harbored the laminin-binding protein (eno) gene, while all MRSA isolates harbored intracellular adhesion D (icaD), clumping factors A and B (clfA and clfB) genes. The presence of agrI and elastin-binding protein (ebpS) genes was significantly associated with biofilm production in MSSA and MRSA isolates, respectively. In addition, agrI gene was also significantly correlated with oxacillin, cefoxitin, and fluoroquinolone resistance. Conclusions: The high prevalence of biofilm and slime production among MSSA and MRSA isolates correlates well with the detection of a high prevalence of biofilm-associated genes and agr quorum sensing system. A significant association of agrI gene was found with cefoxitin, oxacillin, and fluoroquinolone resistance. A more focused approach targeting biofilm-associated and quorum sensing genes is important in developing new surveillance and treatment strategies against S. aureus biofilm infection. [ABSTRACT FROM AUTHOR]

In poultry, Escherichia coli infections lead to substantial deaths and financial losses for producers each year. This study aimed to investigate the prevalence of E. coli from water pipes and drinkers in broiler farms, to characterize the isolated E. coli strains in terms of serotypes, biofilm production degree, presence of the adrA gene. The gene “adrA” encodes for the adhesion regulating protein A. adrA is a protein that plays a role in regulating the adhesion and biofilm formation of E. coli bacteria., and the efficacy of various disinfectants on E. coli biofilms. A total of 100 swab samples were collected from drinking water pipes and drinkers from different broiler farms in Giza and Dakahlia governorates in Egypt. Out of them, 18 E. coli serogroups were identified in 50 positive samples, and the most predominant serogroup was O91, which showed the highest incidence (20%), followed by serotypes O78 (18%), and O26 (8%). Microtiter-plate test for determination of biofilm production for 50 E. coli isolates were performed. PCR was done for the detection of the virulence gene adrA in the 13 strong biofilm E. coli isolates, and the results revealed that 100% were positive for the virulence gene. The effect of disinfectants on E. coli was studied by using ZnO nanoparticles, acidifiers, and quaternary ammonium dioxide. This study found a high prevalence of E. coli in water samples, identified various E. coli serotypes, observed biofilm production, and determined the effectiveness of different disinfectants on E. coli isolates. [ABSTRACT FROM AUTHOR]

Antimicrobial-resistant bacteria in poultry meat threaten the public health. The present study was designed to detect the presence of Enterococcus species in poultry meat collected from Mansoura retail outlets with characterization of vancomycin-resistant enterococci (VRE). Thus, poultry meat samples (breast and thigh) were collected from separate grocery stores around Mansoura city, Egypt. By conventional and molecular methods, out of the total examined samples (n=120), 44 E. fecalis isolates have been recovered with a percentage of 36.66%. All strains were assessed for their antimicrobial susceptibility using disc diffusion method, the highest rate of resistance (100%; 44/44) was displayed to ceftazidime, streptomycin, gentamycin, and clindamycin, while, a resistance rate of 36.3%, 40.9%, 68.1% and 77.2% were displayed against ciprofloxacin, penicillin, erythromycin and vancomycin respectively. Interestingly, all isolates exhibited multidrug resistance (MDR; Resistance to three or more antimicrobial class). Screening vancomycin -resistant strains (n= 34) by PCR for the presence of vancomycin resistance genes, vanA was identified in 47.1% vanB in 33.4%, vanC1 in 14.7% and vanC-2 C-3 in 5.9%. By testing the ability of the isolated strains for the biofilm production by Congo Red Method, 31.8 % of the tested isolates were tested positive. Hence, standard manufacturing procedures and adequate hygiene conditions must be integrated into all phases of poultry meat preparation, production and consuming, and public knowledge should be improved. [ABSTRACT FROM AUTHOR]

Multidrug-resistant Enterobacter strains that harbour Klebsiella pneumoniae carbapenemase and Extended Spectrum β-Lactamases genes are a therapeutic challenge in hospitals that have made infection control and antibiotic therapy difficult and use of natural compounds such as thymol is interesting in the treatment of infections. Sixty-seven Enterobacter spp. isolates were obtained from patients admitted to hospitals in Hamadan and Tehran. Antimicrobial susceptibility, ESBLs and KPC genes detection and biofilm production of isolates were measured. The results showed that the highest and lowest antibiotic resistance were related to ceftazidime (82.1%) and tigecycline (3%), respectively. Also, 79.1% of the isolates were MDR. The highest presence of genes was related to TEM (100%), SHV (82%), CTX-M (77%) and KPC (8.96%) genes. The MIC and MBIC of thymol were obtained 8-31 μg/ml and16-62 μg/ml, respectively. Use of thymol, as an aid in antibiotic therapy is recommended. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa (PAO1) is an opportunistic pathogen, lethal in immunocompromised individuals. The clinical management of PAO1 infections still depends deeply on antibiotic therapy. However, this therapy has been alarmingly overpowered by growing bacterial resistance mechanisms over the years. One of these bacterial mechanisms is quorum sensing (QS). QS is involved in the production of biofilm, rhamnolipids and pyocyanin, among other factors. The present study aimed to study the effect of the mutations in the genes of rubredoxin (Rub A1 and Rub A2) and glutaredoxin (GLRx) in the production of virulence traits and susceptibility of PAO1 to the antibiotic ciprofloxacin (CIP) and to infection by a phage cocktail. Rub A1, Rub A2, and GLRx showed a decrease in the expression of genes lasI, lasR, mvfR, and rpsL when compared to the wild type, PAO1. Rub A1 and Rub A2 also showed a decrease in the expression of the gene pqsA, while the mutant GLRx showed an increase of over 200% in expression compared to PAO1. The biofilm produced by the mutants Rub A1, Rub A2, and GLRx increased more than 1.5 times in comparison to PAO1, with statistical significance (p < 0.0001). In the viability assay, the mutant strain Rub A2 was the most susceptible to ciprofloxacin in both concentrations tested (p < 0.0001). The production of proteases increased in the mutant strains when compared to PAO1 (p < 0.05). However, there was a decrease in the production of rhamnolipids and pyocyanins in the mutant strains. In the phage assay, we could perceive a reduction in the growth of the mutant strains when compared to PAO1. Additionally, after the addition of the phages, all the strains showed susceptibility to the phage assay (p < 0.0001), observed in the decrease in the absorbance values. These results may highlight the relevance of the genes Rub A1, Rub A2, and GLRX in the proliferation and treatment of infections with PAO1. Overall, this study gives preliminary insights into how gene expression may be helpful in strategies to overcome antibiotic resistance. [ABSTRACT FROM AUTHOR]

Vibrio spp. including Vibrio cholerae and V. parahaemolyticus are the major causative agent of diarrhea involved in seafood consumption. Yala is a southern border province in Thailand where no seafood sources are provided. Thus, it is necessary to import several seafood products from neighboring provinces. The risk of Vibrio spp. replication is increased during seafood transport. Therefore, the objectives of this study were to isolate and characterize V. cholerae and V. parahaemolyticus from seafood in Yala and to investigate their genetic relationships with virulent and clinical strains. A total of 100 Vibrio isolates were obtained from four different sample types in retail markets. It was found that two-thirds of all isolates were yellow colonies on TCBS agar. Using PCR with specific primers, 34 % of V. cholerae and 8 % of V. parahaemolyticus were identified. To classify the virulence strains, Vibrio spp. were positive for hlyA and tdh, 17 and 1 %, respectively. Moreover, 54 % of Vibrio isolates were able to produce biofilm and 28 % of those isolates showed a high level of biofilm production. All representative strains of V. cholerae presented ß-hemolysin on blood agar correlated to hlyA while representative strains of V. parahaemolyticus presented ?-hemolysin and ß-hemolysin on blood agar. In addition, ERIC-PCR provided different DNA profiles of representative V. cholerae and V. parahaemolyticus which some strains showed a correlation with clinical strains and virulent strains. Therefore, these findings might indicate the risk of Vibrio infections for seafood consumers, especially in Yala province where seafood needs to be imported from other provinces. [ABSTRACT FROM AUTHOR]

Biofilm formation is a critical factor for K. pneumoniae's ability to cause disease, as it shields the bacteria from the immune response of serum and phagocytosis. K. pneumoniae commonly employs biofilm formation as a survival strategy. A global issue of bacteria developing resistance to multiple drugs causes numerous deaths each year. To address the rising prevalence of drug-resistant bacteria, various legislative actions have been implemented to restrict or eliminate the use of antibiotics. Klebsiella pneumoniae, a bacteria commonly associated with healthcare-related infections, exhibits high levels of antibiotic resistance and is known for its ability to form biofilms. This research aimed to isolate and identify K. pneumoniae strains obtained from clinical samples in Samawwa city, Iraq, and also determining their antibiotic resistance patterns and capacity for biofilm production. The isolation of K. pneumoniae was carried out on inpatients in Samawwa between September and December 2022. The identification process involved analyzing colony morphology on selective media (Hichrom agar and ESBL agar), microscopic examination, and biochemical testing. Antibiotic susceptibility testing and biofilm-producing capacity assessment were conducted using the Kirby-Bauer disk diffusion method and microtiter plate assays which is known as a 96- well plate, is a quantitative method used with a microplate reader to determine the production of biofilm, respectively .A total of 85(40%) K. pneumoniae isolates were isolated from 215 total clinical samples during the study. The majority of the samples were gathered from male and female patients spanning an age range of 3 to 90 years. These samples were primarily acquired from urine specimens.(67%). The majority of K. pneumoniae strains exhibited high levels of antibiotic resistance, except for meropenem, imipenem, and norfloxacin, which showed better inhibition .18%; 7% and 7.5% of resistance, respectively. In addition, 24 isolates were tested for capacity to biofilm production, 17 (63%) isolates were biofilm producers, with 10 (41%) isolates as moderate, and 6 (38%) isolates as weak biofilm producers. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is one of the biofilm-forming pathogens in the food industry. Biofilms can be formed on both animate and inanimate surfaces throughout the food chain. This poses a tough challenge resulting in changes in the food industry’s cleaning and disinfection dynamics. In this study, Pseudomonas aeruginosa (P. aeruginosa) was detected, using the morphological and biochemical methods, in 12 out of 32 isolates of Gram-negative motile rod-shaped isolates “Pseudomonas spp.” isolated from meat products, and 5 of the 12 (41.7%) P. aeruginosa strains were strong biofilm-producers using crystal violet microtiter plate assay. The PCR results revealed that 5 isolates of P. aeruginosa were encoding the aminoglycoside regulator response (arr) gene responsible for the biofilm production, with an incidence of 41.7 %; 2 (40%) of which were detected in the minced beef strains, 1 (20%) for each of the sausage and burger strains while it could not be identified in luncheon strains. Thymol and cinnamon essential oils were used to control P. aeruginosa strains and their biofilm in vitro using the microtiter plate assay. Applying the EO caused a reduction in P. aeruginosa biofilm formation. While clove EO did not inhibit the growth of P. aeruginosa using the agar well diffusion method. The application of thymol and cinnamon Eos in meat contact surfaces or meat products could inhibit the growth of P. aeruginosa as well as reduce the biofilm formation resulting in preventing serious health and economic problems.

The members of Microbacterium isolated from different environments are known to form peptidoglycan. In this study, we compared the biofilm-forming abilities of Microbacterium sp. PAMC22086 (PAMC22086), which was isolated from the soil in the South Shetland Islands and Microbacterium sp. PAMC21962 (PAMC21962), which was isolated from algae in the South Shetland Islands. The analysis of average nucleotide identity and phylogeny of PAMC22086 revealed a 97% similarity to Microbacterium oxydans VIU2A, while PAMC21962 showed a 99.1% similarity to Microbacterium hominis SGAir0570. For the comparative genomic analysis of PAMC22086 and PAMC21962, the genes related to biofilm formation were identified using EggNOG and KEGG pathway databases. The genes possessed by both PAMC22086 and PAMC21962 are cpdA, phnB, rhlC, and glgC, which regulate virulence, biofilm formation, and multicellular structure. Among the genes indirectly involved in biofilm formation, unlike PAMC21962, PAMC22086 possessed csrA, glgC, and glgB, which are responsible for attachment and glycogen biosynthesis. Additionally, in PAMC22086, additional functional genes rsmA, which is involved in mobility and polysaccharide production, and dksA, GTPase, and oxyR, which play roles in cell cycle and stress response, were identified. In addition, the biofilm-forming ability of the two isolates was examined in vivo using the standard crystal violet staining technique, and morphological differences in the biofilm were investigated. It is evident from the different distribution of biofilm-associated genes between the two strains that the bacteria can survive in different niches by employing distinct strategies. Both strains exhibit distinct morphologies. PAMC22086 forms a biofilm that attaches to the side, while PAMC21962 indicates growth starting from the center. The biofilm formation-related genes in Microbacterium are not well understood. However, it has been observed that Microbacterium species form biofilm regardless of the number of genes they possess. Through comparison between different Microbacterium species, it was revealed that specific core genes are involved in cell adhesion, which plays a crucial role in biofilm formation. This study provides a comprehensive profile of the Microbacterium genus's genomic features and a preliminary understanding of biofilm in this genus, laying the foundation for further research. [ABSTRACT FROM AUTHOR]

An opportunistic bacterium called Acinetobacter baumannii has significantly increased the frequency of infections in recent years. With only a limited number of “traditional” virulence factors, It is infections have spread rapidly through hospitals across the globe. The present study aimed to work out the relationship between the multi-drug resistance (MDR) of A. Baumannii and biofilm formation. A total of 150 samples were collected from various clinical sources from different age groups and gender patients in Ghazi AL Hariri Hospital and Baghdad Teaching laboratories in Medical City in Baghdad, Iraq from December 2021 to March 2022. Microscopical inspection and cultural features on various culture media, including culturing on selective medium CHROMagar, were used to identify bacterial isolates. The characteristics of the isolates were then established by some biochemical tests. Identification was confirmed using the Vitek-2 system with an accuracy of 99%, which revealed that only (50) isolates were given identical morphological characteristics and biochemical tests belonging to Acinetobacter baumannii isolates. 28 (56%) isolates were collected from burns. 10 isolates (20%) and 9 isolates (18% were collected from wound and sputum cultures of A. baumannii, respectively, while only 3 isolates (6%) were from urine culture. The susceptibility test for all the fifty clinical isolates of A. baumannii was performed against 10 different antibiotics. The results showed that A. baumannii isolates were Multidrug-resistant (MDR) (98%), while the other (2%) of the isolates were extensively drug-resistance (XDR) to the majority of antibiotics tested. All 50 isolates in the present study were subjected to the micro-titer plate (MTP) assay method (96 walls). The results indicated that strong biofilm was detected in 40 (80.0%) of the tested isolates. Thirty bacterial isolates were were found to be MDR and had strong biofilm production. [ABSTRACT FROM AUTHOR]

This study investigates in vitro biofilm production. Presence of ica A and D genes in methicillin-resistant Staphylococcus aureus was evaluated for biofilm production by the microtiter plate method. Between December 2020 and October 2021, out of 215 clinical specimens were collected from patients with pulmonary fibrosis, pneumonia, bacteremia, chronic burns, deep wounds, urinary tract infection and catheterized patients. Out of which 45 MRSA isolates were identified by the susceptibility test utilizing cefoxitin and the occurrence of mecA gene for resistance for this antibiotic verified by polymerase chain reaction technique. A sensitivity test was conducted for five other antibiotics. All MRSA isolates were producers of biofilms but the formation of robust biofilms by 42% of MRSA isolates, 20% of isolates was intermediate and 38% of isolates weak. Formerly ica A and D genes, responsible for polysaccharide intracellular adhesin dependent biofilm formation were investigated in all MRSA isolates using the polymerase chain reaction technique. ica A were detect in 33 (73.3%) of the isolates and was lacking in 12 (26.6%) of the isolates. ica D gene was present in 38 (84.4%) isolates and was lacking in 7 (15.5%). However, the total number of isolates that contained icaA and D genes was 10 (22.2%). The most noteworthy finding was that the five weak isolates lacked any genes. Thus indicating that these isolates are capable of producing biofilm without the need for ica in order to make polysaccharide intracellular adhesin that means the isolates have an ability to form biofilm in ica independent biofilm mechanisms. [ABSTRACT FROM AUTHOR]

The study aimed to determine the relationship between antibiotic resistance and the ability to produce biofilm of E.coli isolated from sheep in Nineveh Governorate. One hundred four fecal swabs were collected from healthy sheep from 1st February to 5th March 2022. Standard microbiological methods include culture on eosin methylene blue agar (EMB) and MacConkey agar, confirmed by Gram’s Stain and biochemical tests, then polymerase chain reaction (PCR) assay for the specific gene of E.coli (uidA). Antibacterial resistance for 12 types of antibiotics and biofilm production tests were done by Congo red agar. The results showed that 92 samples at a rate of 88.46% were positive for the E.coli isolates; the study also showed that 71 isolates at a rate of 77.17% of E.coli isolates could produce biofilm. The study concluded that biofilm-producing E.coli in both forms strong and weak appear higher resistant to antibiotics other than the non-productive ones. Therefore, searching for other methods to test bacterial sensitivity to antibiotics that consider many factors such as biofilm production and extended-spectrum beta-lactamases is necessary.

Aim:The incidence of fungal infections has increased today, and antifungal resistance has increased in such infections. It is known that most infections produced by Candida species are associated with biofilm formation.Materials and Methods:In this study, 192 patients diagnosed with yeast cytologically in cervico-vaginal smears between September 2015 and August 2020 were investigated.Results:When all Candida species studied with Congo Red Agar were evaluated, biofilm positivity was found to be 61.4% in non-albicans Candida species and 38.6% in C. albicans. Biofilm positive non-albicans Candida species were identified as 11 (15.7%) C. glabrata, 11 (15.7%) C. tropicalis, 6 (8.6%), C. guillermondii and 6 (8.6%) C. krusei.Conclusion:In fungal infections, the biofilm produced by the agent is directly proportional to antifungal resistance and invasion of the infection. Therefore, determining the biofilm production of the causative fungus is important in planning the treatment.

Background: Bacterial biofilm formation (BBF) proves itself to be in the spotlight of microbiology research due to the wide variety of infections that it can be associated with, the involvement in food spoilage, industrial biofouling and perhaps sewage treatment. However, BBF remains difficult to study due to the lack of standardization of the existing methods and the expensive equipment needed. We aim to describe a new inexpensive and easy to reproduce protocol for a 3D-printed microfluidic device that can be used to study BBF in a dynamic manner. Methods: We used the SolidWorks 3D CAD Software (EducationEdition 2019–2020, Dassault Systèmes, Vélizy-Villacoublay, France) to design the device and the Creality3D Ender 5 printer (Shenzhen Creality 3D Technology Co., Ltd., Shenzhen, China) for its manufacture. We cultivated strains of Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. For the biofilm evaluation we used optical coherence tomography (OCT), scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and crystal violet staining technique. Results: Based on the analysis, Enterococcus faecalis seems to produce more biofilm in the first hours while Pseudomonas aeruginosa started to take the lead on biofilm production after 24 h. Conclusions: With an estimated cost around €0.1285 for one microfluidic device, a relatively inexpensive and easy alternative for the study of BBF was developed. [ABSTRACT FROM AUTHOR]

Escherichia coli ST131 is a pandemic clone with high antibiotic resistance, and it is a major causative agent of urinary tract infection (UTI) and bloodstream infections. This study evaluated the distribution and expression of virulence genes and genotyping of E. coli O25b/ST131 by Multi-locus variable number tandem repeat analysis (MLVA) method among UTI in patients at Tehran hospitals, Iran. A total of 107 E. coli isolates were collected from UTI patients. Polymerase chain reaction (PCR) amplification of the pabB gene was used to identify E. coli O25b/ST131 and the prevalence of sat and hlyA virulence genes was also analyzed. The microtiter method quantified biofilm formation ability in E. coli O25b/ST131. The Real-Time PCR (qRT-PCR) was performed to evaluate the expression of sat and hlyA genes. Finally, MLVA was performed for E. coli O25b/ST131 genotyping by targeting seven tandem repeats. SPSS-16 software was used for statistical analysis. Molecular study showed that 71% of isolates carried the pabB gene and were considered E. coli O25b/ST131 strains. Also, 45.8% and 17.8% of isolates carried sat and hlyA genes, respectively. The 57.9% isolates had biofilm formation ability. Expression of the studied virulence genes showed an increase in strong biofilm producing E. coli O25b/ST131 strains. A total of 76 (100%) E. coli O25b/ST131 strains were typed by the MLVA method. High prevalence of E. coli O25b/ST131 isolates in UTI patients can be a serious warning to the treatment due to the high antibiotic resistance rate, expression of virulence genes, and biofilm formation. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Pseudomonas are among psychrophilic bacteria and have been reported in various studies as the predominant spoilage bacterial in slaughter carcass. The aim of this study was to track Pseudomonas spp. from different stages of the slaughter line, slaughterhouse environment and equipment and drop in the packaging. Characteristics such as pigment production, movement pattern and biofilm formation capability of the isolates were also determined. For this purpose, 108 samples were sampled from three industrial poultry slaughterhouses in Tabriz. According to the results, the highest contamination was detected in the samples of the floors, abdominal cavity of carcass and drip samples, respectively. The lowest contamination was observed in the samples related to drinking water, live chicken breast swab and scalder, respectively. The average movement of the Swimming type was significantly (p ≤ 0.001) higher than the two types of Swarming and Twitching movements. And in terms of pigment production, the dominant color was green. Moreover, most of the isolates were able to form biofilms and about 30% of the isolates had moderate and strong ability to produce biofilms. In conclusion, most of the Pseudomonas spp. contamination occurs through different parts of the slaughter line and also the equipment and environment of the slaughterhouse. Due to the biofilm production capacity of Pseudomonas isolates, the issue of proper and more effective washing and disinfection of the slaughter line and equipment is of particular importance.

Helicobacter pylori (H. pylori) causes several gastrointestinal diseases. Its virulence factors contributing to disease development include biofilm formation, cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA) proteins that induce host tissue damage. In addition, urease activity enables H. pylori growth in the gastric acidic environment. This work aimed to characterize bacterial factors associated with biofilm production among 89 clinical H. pylori isolates, collected from patient gastric biopsies. Biofilm production was detected using the crystal violet method. PCR was performed to determine vacA genotype (s1m1, s1m2, s2m1 and s2m2) and cagA gene presence. Urease activity was measured via the phenol red method. Susceptibility to six antibiotics was assessed by the Etest method. Most H. pylori isolates produced biofilm. No association was found between biofilm-formation capacity and cagA presence or vacA genotype. Urease activity levels varied across isolates; no association was found between biofilm-formation and urease activity. Clarithromycin resistance was measured in 49 % of the isolates. Isolates susceptible to tetracycline were more commonly strong biofilm producers. In contrast, a significantly higher rate of strong biofilm producers was observed among resistant isolates to amoxicillin, levofloxacin and rifampicin, compared to susceptible isolates. Non-biofilm producers were more common among isolates sensitive to rifampicin and metronidazole, compared to resistant isolates. Further studies are needed to understand the factors that regulate biofilm production in order to search for treatments for H. pylori biofilm destruction. • We assessed association between virulence H. pylori 's factors among 89 isolates. • Most H. pylori isolates produced biofilm. • Biofilm-formation capacity was not associated with cagA presence or vacA genotype. • Biofilm-formation and urease activity were not associated. • Non-biofilm production was associated with susceptibility to metronidazole. [ABSTRACT FROM AUTHOR]

Serpentine soils exhibit unique chemical properties, characterized by high concentrations of heavy metals (usually Ni, Fe, Cr, and Co) and limited availability of micronutrients, rendering them unfavorable for numerous microbial species. In response, serpentine bacteria have evolved various adaptive strategies that enable their undisturbed proliferation. Furthermore, serpentine habitats have diverse bacterial communities with potential use in industrial biotechnology and agriculture. Thus, the primary objective of this study was to examine the heavy metal tolerance and quantify biofilm production of bacterial serpentine isolates. In total, 24 sequenced rhizospheric and endophytic serpentine isolates associated with Robinia pseudoacacia L. were retrieved from the bacterial repository of the University of Sarajevo - Institute for Genetic Engineering and Biotechnology. Heavymetal tolerance was evaluated on tryptone yeast agar plates supplemented with Ni, Cu and Co salts with final metal concentrations 100 mg/L and 200 mg/L. After 15 day incubation period at room temperature, positive results were confirmed by observable growth. Biofilm production was assessed utilizing the Microtiter plate assay (MPA) with modifications to accommodate rhizospheric and endophytic bacteria. Absorbance was measured at 570 nm using a Thermo Scientific MultiskanTM reader. The biofilm production was graded based on OD according to the standard scale: nonproducers, weak, moderate and strong producers. All the rhizospheric isolates tolerated 100 mg/L concentration of the tested metals while only one isolate failed to grow in the presence of 200 mg/L Ni. No isolates were able to tolerate 200 mg/L Cu. In contrast, tolerance to the tested heavy metals was not a common trait in endophytic isolates. Similar trend was observed regarding biofilm production. While rhizospheric bacteria consistently produced biofilms (2 moderate and 12 low-producers), only three endophytic isolates yielded low biofilm production. Rhizospheric Pseudomonas isolates exhibited strong heavy metal tolerance and prominent biofilm producing abilities as opposed to limited tolerance and weak biofilm production by endophytic Bacillus, Brevibacillus and Lysinibacillus. Bacteria produce biofilms as a survival strategy in a response to environmental stressors. Biofilm production requires energy expenditure and endophytes, having procured nutrients and protection by plants, forego this ability. It is an important input when selecting isolates for biotechnological applications. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa (PAO1) is an opportunistic pathogen, lethal in immunocompromised individuals. The clinical management of PAO1 infections still depends deeply on antibiotic therapy. However, this therapy has been alarmingly overpowered by growing bacterial resistance mechanisms over the years. One of these bacterial mechanisms is quorum sensing (QS). QS is involved in the production of biofilm, rhamnolipids and pyocyanin, among other factors. The present study aimed to study the effect of the mutations in the genes of rubredoxin (Rub A1 and Rub A2) and glutaredoxin (GLRx) in the production of virulence traits and susceptibility of PAO1 to the antibiotic ciprofloxacin (CIP) and to infection by a phage cocktail. Rub A1, Rub A2, and GLRx showed a decrease in the expression of genes lasI, lasR, mvfR, and rpsL when compared to the wild type, PAO1. Rub A1 and Rub A2 also showed a decrease in the expression of the gene pqsA, while the mutant GLRx showed an increase of over 200% in expression compared to PAO1. The biofilm produced by the mutants Rub A1, Rub A2, and GLRx increased more than 1.5 times in comparison to PAO1, with statistical significance (p < 0.0001). In the viability assay, the mutant strain Rub A2 was the most susceptible to ciprofloxacin in both concentrations tested (p < 0.0001). The production of proteases increased in the mutant strains when compared to PAO1 (p < 0.05). However, there was a decrease in the production of rhamnolipids and pyocyanins in the mutant strains. In the phage assay, we could perceive a reduction in the growth of the mutant strains when compared to PAO1. Additionally, after the addition of the phages, all the strains showed susceptibility to the phage assay (p < 0.0001), observed in the decrease in the absorbance values. These results may highlight the relevance of the genes Rub A1, Rub A2, and GLRX in the proliferation and treatment of infections with PAO1. Overall, this study gives preliminary insights into how gene expression may be helpful in strategies to overcome antibiotic resistance.

The uprising problem of the Presence of Multi Drug Resistant (MDR) pathogenic bacteria is an emerging obstacle facing food safety. This study purposed to evaluate the antibiotic-resistant profile regarding the Presence of MRSA and biofilm production. After collection of 225 samples (30 chicken fillet, 30 chicken nuggets, 30 chicken shawarma, 15 chicken luncheon, 60 chicken stock cubes and 60 imported frozen chicken meat) from local markets in Cairo and Giza (Egypt), they were examined bacteriologically for staphylococcus aureus using mannitol salt agar and blood agar, The occurrence of staphylococci was 127/225 (56.4%). 16.8% of the samples were S.aureus (38/225), while, 39.5% (89/225) were coagulase-negative staphylococci. S. aureus recovered from 8.3% of frozen chicken meat, 13.3% of chicken fillet, 23.3% of chicken nuggets, 46.6% of chicken shawarma, 33.3% of chicken luncheon, and 5% of chicken stock cubes. Resistance against 13 antibiotics was determined using Kirby-Bauer disc diffusion test, 100%, 78.9%, and 52.6% of the isolates were resistant to penicillin G, tetracycline, and amoxicillin. Clavulanic acid respectively, while 26.3% were resistant to methicillin. On the other hand, the isolates showed high sensitivity to vancomycin, clindamycin, and chloramphenicol with percentages 97.3%, 81.5%, and 68.4% respectively. The resistant strains to methicillin were tested by PCR for the presence of mecA gene, the result was 100% (10/10) positive for mecA gene. The isolates were phenotypically tested for the ability of biofilm formation using the Tube method that divided S. aureus isolates into 4 grades: strong biofilm former, moderate biofilm former, weak biofilm former, and non-biofilm former with percentages18.4%, 15.7%, 13.1%, and 52.6% respectively. To conclude, the increased prevalence of S.aureus in chicken meat products pinpoints the unhygienic condition of food processing, moreover, the occurrence of MDR S. aureus in chicken meat products might lead to alarming public health threats so there is an alerting need for rational use of antibiotics. [ABSTRACT FROM AUTHOR]

The study aimed to determine the relationship between antibiotic resistance and the ability to produce biofilm of E.coli isolated from sheep in Nineveh Governorate. One hundred four fecal swabs were collected from healthy sheep from 1st February to 5th March 2022. Standard microbiological methods include culture on eosin methylene blue agar (EMB) and MacConkey agar, confirmed by Gram's Stain and biochemical tests, then polymerase chain reaction (PCR) assay for the specific gene of E.coli (uidA). Antibacterial resistance for 12 types of antibiotics and biofilm production tests were done by Congo red agar. The results showed that 92 samples at a rate of 88.46% were positive for the E.coli isolates; the study also showed that 71 isolates at a rate of 77.17% of E.coli isolates could produce biofilm. The study concluded that biofilm-producing E.coli in both forms strong and weak appear higher resistant to antibiotics other than the nonproductive ones. Therefore, searching for other methods to test bacterial sensitivity to antibiotics that consider many factors such as biofilm production and extended-spectrum beta-lactamases is necessary. [ABSTRACT FROM AUTHOR]

Methicillin resistant Staphylococcus aureus (MRSA) is the most common pathogenic bacteria in the hospitals and communities, the ability to form biofilm is considered the main cause of Staphylococcus pathogenicity since it provides resistance to both antibiotics and host immune response, so this study was aimed to evaluate the biofilms formation and its association with antibiotic resistance in clinical isolates of MRSA, in order to achieve this aim, 237 samples were collected from different patients with wounds infections after surgeries and samples from operations galleries from varies hospitals in Baghdad,68 isolates out of 237 were subjected to Staphylococcus aureus according to conventional methods Additionally, the S. aureus isolates were re-identified by molecular method. The results for Susceptibility of 68 S.aureus isolates against 22 antimicrobial agents revealed all isolates were resistant (100%) to Cefotaxime, and showed resistance to Ceftriaxone, Oxacillin, Cefipime, Cefoxitin, ampicillin, Penicillin, Nalidixicacid, erythromycin in percentage (99, 97,97,87, 87, 79, 75, 65 )% respectively while other isolates showed variety in their resistant to other antimicrobial agents. while all 68 isolates were sensitive to Nitrofurantoin which is considered the most effective agent against the isolates. All 68 isolates were identified as MRSA on HiCromeMeReSa Agar Base medium, but 66 among 68 isolates were methicillin resistant in antibiotic sensitivity test, while 67 isolates had a positive reaction when detecting mecA gene using Polymerase Chain Reaction (PCR) technique. The finding of biofilm detection by microtiter plate method (MTPs) showed that 56 of 68 isolates produced biofilm in different degrees, while 66 (97%) among 68 isolates possessed the icaAD gene using PCR. [ABSTRACT FROM AUTHOR]

The members of Microbacterium isolated from different environments are known to form peptidoglycan. In this study, we compared the biofilm-forming abilities of Microbacterium sp. PAMC22086 (PAMC22086), which was isolated from the soil in the South Shetland Islands and Microbacterium sp. PAMC21962 (PAMC21962), which was isolated from algae in the South Shetland Islands. The analysis of average nucleotide identity and phylogeny of PAMC22086 revealed a 97% similarity to Microbacterium oxydans VIU2A, while PAMC21962 showed a 99.1% similarity to Microbacterium hominis SGAir0570. For the comparative genomic analysis of PAMC22086 and PAMC21962, the genes related to biofilm formation were identified using EggNOG and KEGG pathway databases. The genes possessed by both PAMC22086 and PAMC21962 are cpdA, phnB, rhlC, and glgC, which regulate virulence, biofilm formation, and multicellular structure. Among the genes indirectly involved in biofilm formation, unlike PAMC21962, PAMC22086 possessed csrA, glgC, and glgB, which are responsible for attachment and glycogen biosynthesis. Additionally, in PAMC22086, additional functional genes rsmA, which is involved in mobility and polysaccharide production, and dksA, GTPase, and oxyR, which play roles in cell cycle and stress response, were identified. In addition, the biofilm-forming ability of the two isolates was examined in vivo using the standard crystal violet staining technique, and morphological differences in the biofilm were investigated. It is evident from the different distribution of biofilm-associated genes between the two strains that the bacteria can survive in different niches by employing distinct strategies. Both strains exhibit distinct morphologies. PAMC22086 forms a biofilm that attaches to the side, while PAMC21962 indicates growth starting from the center. The biofilm formation-related genes in Microbacterium are not well understood. However, it has been observed that Microbacterium species form biofilm regardless of the number of genes they possess. Through comparison between different Microbacterium species, it was revealed that specific core genes are involved in cell adhesion, which plays a crucial role in biofilm formation. This study provides a comprehensive profile of the Microbacterium genus’s genomic features and a preliminary understanding of biofilm in this genus, laying the foundation for further research.

Aims: The ability of the pathogenic bacterium Pseudomonas aeruginosa to produce biofilms has made it more difficult to treat its infections with current antibiotics. Several genes are involved in biofilm production, and toxin‐antitoxin (TA) loci have been reported to be responsible for the regulation of biofilm‐associated genes. This study was aimed at evaluating various TA loci in P. aeruginosa to find a reliable target in order to disrupt biofilm formation. Methods and Results: Thirty clinical isolates of P. aeruginosa were assessed for biofilm production as well as the presence of various TA loci in their genomes. The relBETA locus was present in all 30 P. aeruginosa isolates but its expression was not detectable in isolates that did not show biofilm production. Quantitative real‐time ‐PCR (q‐PCR) also demonstrated that the expression of relBE was higher in isolates with stronger biofilm‐producing capability. Knocking out the relBE locus in one biofilm‐producing P. aeruginosa isolate led to the cessation of biofilm‐producing capacity in that isolate and eliminated the expression of ndvB, which is among the genes involved in biofilm production. Conclusions: These results inferred the involvement of relBE TA locus in the regulation of biofilm production in P. aeruginosa and indicated the possibility of relBE as an anti‐biofilm target for this pathogen. [ABSTRACT FROM AUTHOR]

Copyright of Namık Kemal Tıp Dergisi is the property of Galenos Yayinevi Tic. LTD. STI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Today, childhood caries is main health related disease it affects many schooling children in many countries especially developed by lactic acid bacteria. So in this present the isolating the 50 lactic acid bacteria from different decay affected children's in Fen Dental Clinic, Tirupur Dt. The emerging bacteria LAB confirmed by phenotype and genotype characterization. After, the pathogen screened for the production of biofilm for to check the resistant mechanism of the Lactobacillus acidophilus. In this study the MTLA1-50 isolates produced strong biofilm were confirmed for the Lactobacillus acidophilus carrying resistant capability. In particularly, the maximum strong biofilm producing strains MTLA32 and MTLA50 followed by other isolates. Due to pre-dominant resistant activity immediately need innovative drug to eliminate biofilm. Currently star fish extract play a vital role in eliminating the bacterial biofilm for this motive in this study chosen the star fish extract in the concentration of 50, 100, 150µl was performed and executed by well diffusion techniques. The results showed the strain No. MTLA32 and MTLA 50 got the maximum zone of inhibition at 150µl (52mm and 38mm) of extract. Hence this research paper proved the star fish extract has a powerful anti-therapeutic medicine mechanism to treat the dental pathogen. [ABSTRACT FROM AUTHOR]

Concerns have been raised regarding co-selection for antibiotic resistance among bacteria exposed to antibiotics used as growth promoters for some livestock and poultry species. Tetracycline had been commonly used for this purpose worldwide, and its residue has been associated with selection of resistant bacteria in aquatic biofilms. This study aimed to determine the resistance profile, the existence of some beta-lactamases genes and the capacity to form biofilm of bacteria isolated from water samples previously exposed to tetracycline (20 mg/L). Thirty-seven tetracycline-resistant bacterial strains were identified as Serratia marcescens, Escherichia coli, Morganella morganii, Pseudomonas aeruginosa, Citrobacter freundii, Providencia alcalifaciens, and Enterococcus faecium. The highest percentage of resistance was for ampicillin (75.75%) and amoxicillin/clavulanic acid (66.66%) in the Gram-negative bacteria and an E. faecium strain showed high resistance to vancomycin (minimum inhibitory concentration 250 μg/mL). Among the strains analyzed, 81.09% had multidrug resistance and eight Gram-negatives carried the blaOXA-48 gene. All strains were able to form biofilm and 43.23% were strong biofilm formers. This study suggests that resistant bacteria can be selected under selection pressure of tetracycline, and that these bacteria could contribute to the maintenance and spread of antimicrobial resistance in this environment. [ABSTRACT FROM AUTHOR]

Abstract Background Coagulase-negative staphylococci (CNS) survive as commensals of skin, anterior nares and external canals of human and were regarded as non-infectious pathogens. However, they are emerging as a major cause of nosocomial infectious due to their ability to form biofilms and high resistance to several classes of antibiotics. This study examines the biofilm forming abilities of 214 clinical CNS isolates using phenotypic and genotypic methods, and determines their antibiotic susceptibility patterns. Methods A total of 214 clinical isolates collected from different clinical samples were identified as CNS and their antibiotic susceptibility determined by CLSI guidelines. The biofilm forming ability of all isolates was determined by three phenotypic methods; Congo red agar (CRA) method, tube adherence method (TM) and tissue culture plate (TCP) method and by genotypic method for the detection of icaAD genes. Results Among all the isolates, S. epidermidis (57.5%) was found the most frequently, followed by S. saprophyticus (18.7%), S. haemolyticus (11.2%), S. hominis (7%), and S. capitis (5.6%). Antibiotic susceptibility pattern demonstrated 91.6% isolates were resistant to penicillin and 66.8% to cefoxitin while 91.1% isolates were susceptible to chloramphenicol. Constitutive and inducible clindamycin resistant phenotype as measured by D-test was seen among 28% and 14.5% of isolates respectively. Tissue culture plate method detected biofilm production in 42.1% isolate followed by 31.8% through tube method while 20.1% isolates were found to produce slime in Congo red agar method. The genotypic assay revealed presence of icaA and icaD genes in 19.2% isolates. Conclusion The study shows a high prevalence of biofilm formation and inducible clindamycin resistance in CNS isolates, indicating the importance of in-vitro biofilm production test and D-test in routine laboratory diagnostics. Implementation of efficient diagnostic techniques for detection of biofilm production in clinical samples can help manage staphylococcal infections and minimize risks of treatment failures in hospitals.

Antimicrobial resistance and biofilm formation by microbial pathogens pose a significant challenge to poultry production systems due to the persistent risk of dissemination and compromise of bird health and productivity. In this context, the study aimed to investigate the occurrence of different multiresistance phenotypes and the biofilm-forming ability of Enterobacteriaceae isolated from broiler chicken excreta in poultry production units in Ceará, Brazil. Samples were collected from three distinct broiler breeding facilities and subjected to isolation, identification, antibiotic susceptibility testing, phenotypic screening for β-lactamases enzymes, and biofilm formation evaluation. Seventy-one strains were identified, being Escherichia coli (37 %) and Proteus mirabilis (32 %), followed by Klebsiella pneumoniae (11 %), Providencia stuartii (9 %), Klebsiella aerogenes (6 %), Alcaligenes faecalis (4 %), and Salmonella sp. (1 %). A significant proportion (87 %) of multiresistant strains were detected. For the phenotypic evaluation of β-lactamases production, strains with resistance to second and third-generation cephalosporins and carbapenems were tested. About 4 of 6 and 10 of 26 were positive for inducible chromosomal AmpC β-lactamase and extended-spectrum β-lactamase (ESBL), respectively. Regarding biofilm formation, it was observed that all MDR strains were capable of forming biofilm. In this sense the potential of these MDR bacteria to develop biofilms becomes a significant concern, representing a real threat to both human and animal health, as biofilms offer stability, antimicrobial protection, and facilitate genetic transfer. • High rates (87 %) of multidrug-resistant Enterobacteriaceae in poultry farms. • Matching between antibiotic resistance profile and antibiotic often used in poultry farms. • All MDR strains demonstrated the ability to form biofilms. • A strong link was found between antibiotic resistance and biofilm formation. [ABSTRACT FROM AUTHOR]

This study aims to test the toxicity of some metallic elements on Salmonella enterica strains and their power to grow and to develop a biofilm to overcome this environmental stress. From 50 selected strains of Salmonella, 70% belong to the Kentucky serotypes that is the most frequent one, followed by the other serotypes such as Amsterdam 6%, anatum 4%, derby 4% Enteritidis 4%, Zanzibar 4%, typhyrimium 2%, gallinaruim 2%, inbondaka 2% and Newport 2%. All the strains have presented the invA invasion gene involved in the virulence and Salmonella infection. Genotypic BOX-PCR analysis of these strains showed 18 profiles, with a discrimination index of 0.93. The Salmonella growth has mainly revealed that the variation of the rates of different metallic elements showed a significant influence on the Salmonella growth. The qualitative, quantitative study and biofilm tubes showed that 40% of the strains have a strong capacity to form biofilm, and the wild-type phenotypes (RDAR; rigid film; Strong), This phenotype varies according to the nature and the concentration of the metal (0.1 mM–1 mM) considered. In the presence of copper, zinc, cobalt, and chromium, the Salmonella strains showed a potent capacity to form a biofilm with a slight variation in the wild-type phenotype. However, when chromium rates increased, Salmonella loses the RDAR morphotype. Addition of mercury and cadmium in the growth medium reduced the production of Salmonella biofilm by around 14 and 15%, respectively, if compared with the control free of metals. [ABSTRACT FROM AUTHOR]

Species of Aspergillus (A.) niger complex and A. flavus complex are predominant molds that are causative agents of otomycoses. The goal of this study was to investigate the clinical presentation, diagnostic procedure, and appearance of relapse in patients with Aspergillus-otomycosis, as well as to determine the biofilm production ability of species isolated in relapse. Thirty patients with laboratory evidenced Aspergillus-otomycosis followed by two check-ups (30 and 60 days after initiation of treatment with antimycotics for local application) were included in the study. For isolation and identification of Aspergillus spp. the standard mycological procedure was applied. Results showed very high sensitivity of microscopy, but 16.7% Aspergillus species required the optimal temperature of 27–28 °C for cultivation. Applied statistical cluster analysis showed a defined specific cluster/group of patients with A. niger complex-otomycosis. Sixty days after diagnosis and treatment initiation, six patients had a relapse, with the same species of Aspergillus genus being the cause. To establish the ability of biofilm production, the modified method described by Pierce and Kvasničková was performed, and all six species isolated in the relapse episode had the ability to produce biofilm. Official criteria and recommendations are needed due to the possibility of misdiagnosis, which leads to the prolongation and complication of the disease. [ABSTRACT FROM AUTHOR]

Cronobacter spp. are opportunistic foodborne pathogens that most often infect neonates and infants through contaminated powdered infant formula. No reports have been published in Serbia on the prevalence of Cronobacter spp. in powdered milk production environments. Consequently, this study aimed to determine the prevalence, molecular characterization, antimicrobial susceptibility, and biofilm‐forming ability of Cronobacter spp. isolated from a milk powder plant. Hundred samples were collected from the production facility. Fifteen Cronobacter sakazakii strains were isolated and identified, giving a contamination rate of 15%. Using multi‐locus sequence typing, the isolates were divided into five sequence types (STs). Cronobacter sakazakii ST4 (50%), ST1 (16.67%), and ST83 (16.67%) were the dominant STs isolated. A novel sequence type (ST759) was identified and registered in the Cronobacter MLST database. The results of the antibiotic susceptibility testing indicated that C. sakazakii strains were susceptible to piperacillin/tazobactam, ampicillin/sulbactam, and amoxicillin/clavulanate, especially to meropenem and cefotaxime. Most of the ST4 showed moderate‐to‐strong biofilm‐forming ability. The presence of clinically relevant isolates (ST4, ST1, ST83, and ST8) revealed that the production plant is likely a potential concern for public health. Finally, finding new sequence types like the one detected in this study (ST759) underlines evolving genetic changes in C. sakazakii. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the antibiotic susceptibility of eighty Escherichia coli isolates from vegetables and food products of animal origin in Tunisia, and to study their genes encoding antibiotic resistance and in vitro biofilm forming capacity. Antimicrobial susceptibilities were determined, as well as PCR investigation of genes associated with antibiotic resistance. Biofilm formation was tested using four different methods: the microtiter plate-, MTT-staining-, XTT-staining-, and the Congo Red Agar assays. High antibiotic resistance rates were observed for amoxicillin (68.7%), amoxicillin/clavulanic acid (73.7%), gentamicin (68.7%), kanamycin (66.2%), nalidixic acid (36.2%), streptomycin (68.7%) and tetracycline (35%). The majority of isolates was multidrug resistant and biofilm producer. MTT testing showed that vegetables isolates were significantly higher biofilm producers compared to foods of animal origins. This study showed that E. coli isolates from food products were reservoirs of genes encoding antibiotic-resistance and have a high propensity to produce biofilm. [ABSTRACT FROM AUTHOR]

Acetic acid bacteria (AAB) produce acetic acid but are also gaining importance as safe microorganisms for producing extracellular polysaccharides (EPSs). The best-known homopolysaccharides among them are cellulose and levan. In addition, acetic acid bacteria also produce heteropolysaccharides, water-soluble acetans. Isolates from the broth of organic and conventional apple cider vinegar production were screened for biofilm production. Phenotypic and genomic diversity of EPS-producing isolates was assessed. The diversity of phenotypically different EPSs of apple cider vinegar isolates was investigated at the gene level for the following novel strains: Komagataeibacter (K.) melomenusus SI3083, K. oboediens SI3053, K. pomaceti SI3133, and Gluconacetobacter (Ga.) entanii SI2084. Strain K. melomenusus SI3083 possesses cellulose operons bcs1, bcs2, and bcs4 together with the type I acetan cluster in the absence of the levan operon, strain K. oboediens SI3053 has the operons bcs1, bcs2, bcs3, and bcs4, the levan operon, and the acetan cluster (type I), and the strains K. pomaceti SI3133 and Ga. entanii SI2084 both contain recently described novel ace-type II cluster in addition to the incomplete operon bcs1. A comparison of the genetic diversity of these EPSs to those of the reference strains suggests that the studied EPSs are not species-descriptive. The results of this study deepen our understanding of the genetic variability of the EPS genes in AAB, thereby enabling us to better characterize and exploit the various insoluble and soluble exopolysaccharides produced by AAB for biotechnological applications in the future. [ABSTRACT FROM AUTHOR]

Ahmed Hazem El-Nagdy,1 Gamal M Abdel-Fattah,2 Ziad Emarah3 1Microbiology Department, Faculty of Dentistry, Horus University, Damietta el gadeeda, Egypt; 2Botany Department, Faculty of Science, Mansoura University, Mansoura, Egypt; 3Medical Oncology Unit Internal Medicine Department Faculty of Medicine, Mansoura University, Mansoura, EgyptCorrespondence: Ahmed Hazem El-NagdyMicrobiology Department, Faculty of Dentistry, Horus University, Damietta el gadeeda, EgyptTel +20 1000953030Email Ahmed_elnagdy@hotmail.comIntroduction: Febrile neutropenia (FN) is the evolution of fever in a patient with neutropenia over 38.0°C. Neutropenia is diagnosed when absolute neutrophil count (ANC) < 1500 cells/μL. FN represents a common complication of cancer treatment. Hence, it is featured to be a major cause of morbidity and mortality in cancer patients. Staphylococcus aureus is one of the most important microorganisms isolated from the blood of febrile neutropenic patients. Infections caused by S. aureus range from mild to life-threatening diseases. Biofilm production by S. aureus is one of the most significant virulence factors of the bacterium as it prevents the penetration of antibiotics. Recently, it has been shown that S. aureus carries the ica operon responsible for biofilm production. The aim of the work is to determine a genotypic characterization that includes not only the detection of icaA and icaD genes in S. aureus but also the determination of their relation to clinical and microbiological features. Empiric antibacterial treatment was recommended for cancer patients receiving chemotherapy.Materials and Methods: The relation between the presence of icaA and icaD and biofilm production was determined in a collection of 66 S. aureus samples from febrile neutropenic patients. Biofilm-forming ability was tested on Congo Red agar plates. Also, the effect of the most sensitive antibiotics on the bacterial cells was determined by an electron microscope.Results: Of the bacterial samples, 48 were biofilm-productive and 18 were non-biofilm productive. For the biofilm productive bacteria, 37.5% were positive for icaA, 22.9% were positive for icaD and 10.4% were positive for both. Linezolid was the most effective antibiotic and it is highly recommended for the treatment of febrile neutropenia caused by biofilm-productive S. aureus. Severe changes were found on the bacterial cell after being treated with Linezolid. The icaA and icaD genes were present in only 50% of biofilm-productive bacteria.Conclusion: The ica operon is present in only 50% of biofilm-productive S. aureus and Linezolid is the best antibiotic against these bacteria.Keywords: febrile neutropenia, Staphylococcus aureus, icaA, icaD, biofilm production

The purpose of this study was to evaluate the antibiotic susceptibility of clinically significant Staphylococcus aureus and its association with biofilm production. The antibiotic resistance pattern and biofilm production by S. aureus isolated from invasive sites such as deep tissue and bone, deep seated pus, blood and other sterile body fluids were studied. The prevalence of multidrug resistant strains and the associated risk factors and co-morbidities were noted. Samples were subjected to antibiotic susceptibility testing using modified Kirby-Bauer disc diffusion method and biofilm production was detected by using microtiter plate assay. Of the total 80 clinically significant invasive S. aureusstrains, resistance to penicillin was observed in 70(88.6%) isolates and 38 (47.5%) isolates were resistant to cephalothin. Resistance to erythromycin was observed in 42(52.5%) isolates and 14(17.5%) isolates were resistant to clindamycin. Resistance to ciprofloxacin was 79.5%(n=63). Resistance to rifampicin was observed in 1 isolate (2.1%) and 1 isolate (1.3%) was resistant to teicoplanin. All the isolates were sensitive to vancomycin, tigecycline and linezolid. Out of the 80 S. aureus strains, 21 (26.3%) strains were biofilm producers and 59(73.75%) strains were non-biofilm producers. Among the biofilm producers, resistance to penicillin (57.14%), cephalothin (57.1%) and ciprofloxacin (57.14%) was higher compared to non-biofilm producers. (penicillin 45.7%, cephalothin 35.6% and ciprofloxacin 38.9%,). The rate of MRSA isolated from invasive infections was high (41.25%). We conclude that MRSA and biofilm-producing strains exhibit higher resistance to antibiotics and hence beta-lactams may not be a good empirical antibiotic of choice, especially in biofilm producers. Clindamycin may be an effective alternative substitute to vancomycin forin MSSA and MRSA treatment. Since the patients improved after appropriate antibiotic treatment, we support the role of an early start of appropriate and adequate antibiotic therapy for better patient outcome. We conclude that S. aureus strains exhibited a high resistance to penicillin, β-lactam, macrolide and fluoroquinolones. The rate of MRSA was found to be 41.25%. MRSA and biofilm producing strains exhibit higher resistance to antibiotics. The high prevalence of MDRSA was high (53.75%), which could potentially pose beas a threat to public health, antibiotic use and patient outcome.

Background: Bacterial biofilm formation (BBF) proves itself to be in the spotlight of microbiology research due to the wide variety of infections that it can be associated with, the involvement in food spoilage, industrial biofouling and perhaps sewage treatment. However, BBF remains difficult to study due to the lack of standardization of the existing methods and the expensive equipment needed. We aim to describe a new inexpensive and easy to reproduce protocol for a 3D-printed microfluidic device that can be used to study BBF in a dynamic manner. Methods: We used the SolidWorks 3D CAD Software (EducationEdition 2019–2020, Dassault Systèmes, Vélizy-Villacoublay, France) to design the device and the Creality3D Ender 5 printer (Shenzhen Creality 3D Technology Co., Ltd., Shenzhen, China) for its manufacture. We cultivated strains of Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. For the biofilm evaluation we used optical coherence tomography (OCT), scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and crystal violet staining technique. Results: Based on the analysis, Enterococcus faecalis seems to produce more biofilm in the first hours while Pseudomonas aeruginosa started to take the lead on biofilm production after 24 h. Conclusions: With an estimated cost around €0.1285 for one microfluidic device, a relatively inexpensive and easy alternative for the study of BBF was developed.

Xylella fastidiosa is a plant pathogen that was recently introduced in Europe and is causing havoc to its agriculture. This Gram-negative bacterium invades the host xylem, multiplies, and forms biofilm occluding the vessels and killing its host. In spite of the great research effort, there is no method that effectively prevents or cures hosts from infections. The main control strategies up to now are eradication, vector control, and pathogen-free plant material. Antimicrobial peptides have arisen as promising candidates to combat this bacterium due to their broad spectrum of activity and low environmental impact. In this work, peptides previously reported in the literature and newly designed analogs were studied for its bactericidal and antibiofilm activity against X. fastidiosa. Also, their hemolytic activity and effect on tobacco leaves when infiltrated were determined. To assess the activity of peptides, the strain IVIA 5387.2 with moderate growth, able to produce biofilm and susceptible to antimicrobial peptides, was selected among six representative strains found in the Mediterranean area (DD1, CFBP 8173, Temecula, IVIA 5387.2, IVIA 5770, and IVIA 5901.2). Two interesting groups of peptides were identified with bactericidal and/or antibiofilm activity and low-moderate toxicity. The peptides 1036 and RIJK2 with dual (bactericidal–antibiofilm) activity against the pathogen and moderate toxicity stand out as the best candidates to control X. fastidiosa diseases. Nevertheless, peptides with only antibiofilm activity and low toxicity are also promising agents as they could prevent the occlusion of xylem vessels caused by the pathogen. The present work contributes to provide novel compounds with antimicrobial and antibiofilm activity that could lead to the development of new treatments against diseases caused by X. fastidiosa. [ABSTRACT FROM AUTHOR]

Chlorination is the oldest and widely practiced method for disinfection of potable water across the globe but some microorganisms survive the chlorine treatment and become resistant. In this study, chlorine-resistant bacteria were isolated from 36 reservoirs of the Municipal Corporation of Greater Mumbai. Water was collected in winter, summer and rainy season. The 8 isolates (out of 89) found to be resistant to 20 ppm of chlorine were identified and belong to the Acinetobacter and Serratia sp. The antibiotic resistance profile showed that the isolates were resistant to a broad spectrum of antibiotics which is of concern. Biofilm production was also observed in most of the isolates. Presence of chlorine-resistant bacteria in drinking water is an alarming situation which needs further analysis especially to understand the further characteristics of these isolates for their antibiotic resistance. [ABSTRACT FROM AUTHOR]

Xylella fastidiosa is a plant pathogen that was recently introduced in Europe and is causing havoc to its agriculture. This Gram-negative bacterium invades the host xylem, multiplies, and forms biofilm occluding the vessels and killing its host. In spite of the great research effort, there is no method that effectively prevents or cures hosts from infections. The main control strategies up to now are eradication, vector control, and pathogen-free plant material. Antimicrobial peptides have arisen as promising candidates to combat this bacterium due to their broad spectrum of activity and low environmental impact. In this work, peptides previously reported in the literature and newly designed analogs were studied for its bactericidal and antibiofilm activity against X. fastidiosa. Also, their hemolytic activity and effect on tobacco leaves when infiltrated were determined. To assess the activity of peptides, the strain IVIA 5387.2 with moderate growth, able to produce biofilm and susceptible to antimicrobial peptides, was selected among six representative strains found in the Mediterranean area (DD1, CFBP 8173, Temecula, IVIA 5387.2, IVIA 5770, and IVIA 5901.2). Two interesting groups of peptides were identified with bactericidal and/or antibiofilm activity and low-moderate toxicity. The peptides 1036 and RIJK2 with dual (bactericidal–antibiofilm) activity against the pathogen and moderate toxicity stand out as the best candidates to control X. fastidiosa diseases. Nevertheless, peptides with only antibiofilm activity and low toxicity are also promising agents as they could prevent the occlusion of xylem vessels caused by the pathogen. The present work contributes to provide novel compounds with antimicrobial and antibiofilm activity that could lead to the development of new treatments against diseases caused by X. fastidiosa.

BackgroundClostridioides difficile (C. difficile) is one of the primary pathogens responsible for infectious diarrhea. Antibiotic treatment failure, occurring in about 30% of patients, and elevated rates of antibiotic resistance pose a major challenge for therapy. Reinfection often occurs by isolates that produce biofilm, a protective barrier impermeable to antibiotics. We explored the association between antibiotic resistance (in planktonic form) and biofilm-production in 123 C. difficile clinical isolates.ResultsOverall, 66 (53.6%) out of 123 isolates produced a biofilm, with most of them being either a strong (44%) or moderate (34.8%) biofilm producers. When compared to susceptible isolates, a statistically higher percentage of isolates with reduced susceptibility to metronidazole or vancomycin were biofilm producers (p < 0.0001, for both antibiotics). Biofilm production intensity was higher among tolerant isolates; 53.1% of the metronidazole-susceptible isolates were not able to produce biofilms, and only 12.5% were strong biofilm-producers. In contrast, 63% of the isolates with reduced susceptibility had a strong biofilm-production capability, while 22.2% were non-producers. Among the vancomycin-susceptible isolates, 51% were unable to produce biofilms, while all the isolates with reduced vancomycin susceptibility were biofilm-producers. Additionally, strong biofilm production capacity was more common among the isolates with reduced vancomycin susceptibility, compared to susceptible isolates (72.7% vs. 18.8%, respectively). The distribution of biofilm capacity groups was statistically different between different Sequence-types (ST) strains (p =0.001). For example, while most of ST2 (66.7%), ST13 (60%), ST42 (80%) isolates were non-producers, most (75%) ST6 isolates were moderate producers and most of ST104 (57.1%) were strong producers.ConclusionsOur results suggest an association between reduced antibiotic susceptibility and biofilm production capacity. This finding reinforces the importance of antibiotic susceptibility testing, mainly in recurrence infections that may be induced by a strain that is both antibiotic tolerant and biofilm producer. Better adjustment of treatment in such cases may reduce recurrences rates and complications. The link of biofilm production and ST should be further validated; if ST can indicate on isolate virulence, then in the future, when strain typing methods will be more available to laboratories, ST determination may aid in indecision between supportive vs. aggressive treatment.

Background: Clostridioides difficile (C. difficile) is one of the primary pathogens responsible for infectious diarrhea. Antibiotic treatment failure, occurring in about 30% of patients, and elevated rates of antibiotic resistance pose a major challenge for therapy. Reinfection often occurs by isolates that produce biofilm, a protective barrier impermeable to antibiotics. We explored the association between antibiotic resistance (in planktonic form) and biofilm-production in 123 C. difficile clinical isolates. Results: Overall, 66 (53.6%) out of 123 isolates produced a biofilm, with most of them being either a strong (44%) or moderate (34.8%) biofilm producers. When compared to susceptible isolates, a statistically higher percentage of isolates with reduced susceptibility to metronidazole or vancomycin were biofilm producers (p < 0.0001, for both antibiotics). Biofilm production intensity was higher among tolerant isolates; 53.1% of the metronidazole-susceptible isolates were not able to produce biofilms, and only 12.5% were strong biofilm-producers. In contrast, 63% of the isolates with reduced susceptibility had a strong biofilm-production capability, while 22.2% were non-producers. Among the vancomycin-susceptible isolates, 51% were unable to produce biofilms, while all the isolates with reduced vancomycin susceptibility were biofilm-producers. Additionally, strong biofilm production capacity was more common among the isolates with reduced vancomycin susceptibility, compared to susceptible isolates (72.7% vs. 18.8%, respectively). The distribution of biofilm capacity groups was statistically different between different Sequence-types (ST) strains (p =0.001). For example, while most of ST2 (66.7%), ST13 (60%), ST42 (80%) isolates were non-producers, most (75%) ST6 isolates were moderate producers and most of ST104 (57.1%) were strong producers. Conclusions: Our results suggest an association between reduced antibiotic susceptibility and biofilm production capacity. This finding reinforces the importance of antibiotic susceptibility testing, mainly in recurrence infections that may be induced by a strain that is both antibiotic tolerant and biofilm producer. Better adjustment of treatment in such cases may reduce recurrences rates and complications. The link of biofilm production and ST should be further validated; if ST can indicate on isolate virulence, then in the future, when strain typing methods will be more available to laboratories, ST determination may aid in indecision between supportive vs. aggressive treatment. [ABSTRACT FROM AUTHOR]