Search

Background: The aim of this study was to assess the disk diffusion technique against E-test as a routine antibiotic susceptibility testing method for Helicobacter pylori., Materials and Methods: Susceptibilities of 301 H pylori clinical isolates were simultaneously profiled by E-test and disk diffusion method for levofloxacin (5-μg disk), clarithromycin (15-μg disk), metronidazole (5-μg disk), amoxicillin (10-μg disk), and tetracycline (30-μg disk). Furazolidone susceptibility was evaluated using a 100-μg disk only. The correlation between MICs by E-test and inhibition zone diameters by disk diffusion was assessed by linear regression analysis., Results: Correlation between inhibition zone diameters and MICs was found for levofloxacin (r = -.932), clarithromycin (r = -.894), and to a minor extent metronidazole (r = -.820). Using the linear regression analysis, the inhibition zone diameter breakpoints were calculated to be 29 mm for levofloxacin, 41 mm for clarithromycin, and 15 mm for metronidazole corresponding to the EUCAST-recommended MIC breakpoints. The susceptibility agreement between E-test and disk diffusion for levofloxacin, clarithromycin, and metronidazole was 98.6%, 96.0%, and 96.7%, respectively. The inhibition zone diameters recorded for the amoxicillin, tetracycline, and furazolidone were large (approximately 60 mm in mean), and a poor correlation was found between inhibition zone diameters and MICs for amoxicillin (r = -.594) and tetracycline (r = -.490)., Conclusions: The disk diffusion can be used as a routine H pylori susceptibility testing method for levofloxacin, clarithromycin, and metronidazole in clinical practice under the described technical conditions. The use of disk diffusion for amoxicillin, tetracycline, and furazolidone susceptibility testing needs to be further studied., (© 2020 John Wiley & Sons Ltd.)

Hemodialysis requires repeated, reliable access to the systemic circulation; therefore, a well-functioning vascular access (VA) procedure is crucial for stable hemodialysis. VA infections (VAIs) constitute the most challenging complication and cause considerable morbidity, loss of access, and even death. In this study, we investigated the molecular profiles of different bacterial isolates retrieved from various types of VA grafts. We collected clinical isolates from hemodialysis patients with VAIs in our institution for the period between 2013 and 2018. We identified the bacterial isolates using standard biochemical procedures; we used a polymerase chain reaction for coagulase-negative staphylococci (CoNS) and Burkholderia cepacia complex (BCC) species identification. The antibiotic resistance and molecular profile were analyzed using the disk diffusion method and multilocus sequence typing, respectively. We studied 150 isolates retrieved from patients with VAI and observed that Staphylococcus aureus was the predominant bacterial species, followed by S. argenteus, BCC, and CoNS. According to multilocus sequence typing data, we identified a wide variety of sequence types (STs) in S. aureus isolates, with ST59, ST45, and ST239 being the predominant types. Burkholderia cepacia with two new ST types, namely ST1723 and ST1724, accounted for most of the BCC infections, along with ST102 B. contaminans, which were mainly isolated from infected tunneled-cuffed catheters. In summary, the increased incidence of S. argenteus and BCC infections provides insights into their potential clinical effects in VAIs. The various STs identified in different bacterial species indicate the high genetic diversity of bacterial species isolated from VAIs in our institution., (© 2020 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

Salmonella enterica serovar Typhimurium (S. Typhimurium [STM]) is a leading cause of nontyphoidal salmonellosis (NTS) worldwide. The pathogenesis of NTS has been studied extensively using a streptomycin-pretreated mouse colitis model with the limited numbers of laboratory STM strains. However, the pathogenicity of the clinically isolated STM (STMC) strains endemic in Thailand in mice has not been explored. The aim of this study was to compare the pathogenicity of STMC strains collected from Northern Thailand with the laboratory STM (IR715) in mice. Five STMC isolates were obtained from the stool cultures of patients with acute NTS admitted to Maharaj Nakorn Chiang Mai Hospital in 2016 and 2017. Detection of virulence genes and sequence type (ST) of the strains was performed. Female C57BL/6 mice were pretreated with streptomycin sulfate 1 day prior to oral infection with STM. On Day 4 postinfection, mice were euthanized, and tissues were collected to analyze the bacterial numbers, tissue inflammation, and cecal histopathological score. We found that all five STMC strains are ST34 and conferred the same or reduced pathogenicity compared with that of IR715 in mice. A strain-specific effect of ST34 on mouse gut colonization was also observed. Thailand STM ST34 exhibited a significant attenuated systemic infection in mice possibly due to the lack of spvABC-containing virulence plasmid., (© 2020 The Societies and John Wiley & Sons Australia, Ltd.)

Consumption of contaminated poultry and poultry products represents a common source of nontyphoidal Salmonella infection. Little is known on the status of Salmonella and their antimicrobial susceptibility in poultry farms in Ethiopia. This study investigated the prevalence, serotype distribution, and antimicrobial susceptibility of nontyphoidal Salmonella among poultry farms in Adama and Modjo towns. Three hundred thirty-four cloacal swabs, 384 fecal droppings of birds, 59 feed, 59 floor swabs, and 36 stools from in-contact humans were collected and processed for Salmonella isolation. Isolates were tested for their susceptibility to 15 antimicrobials using Kirby-Bauer disk diffusion assay. Seventeen (28.8%) of the farms and 24 (2.9%) of the samples from poultry farms and 2.8% (1/36) of stool samples of humans in-contact with poultry were positive for Salmonella. Most of the isolates (n = 21) were recovered from fecal droppings of birds while the remaining isolates were recovered from floor swab samples (n = 2) and cloacal swab sample (n = 1). Only three Salmonella serovars: S. Haifa (n = 14, 56%), S. Anatum (n = 7; 28%), and S. Give (n = 4; 16%) were detected. Poultry farms in Adama town, large flock sized farms, and farms that used antimicrobials were significantly associated with the occurrence of Salmonella (p < .05). Twenty (80%) and 19 (76%) of Salmonella isolates were resistant to streptomycin and tetracycline, respectively. Nineteen (76%) of the isolates were resistant to two or more antimicrobials. Detection of multidrug-resistant strains of Salmonella in poultry farms suggests the need for detailed epidemiological and molecular studies to establish sources of acquisition of resistant Salmonella strains., (© 2020 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

Objective: To find antagonistic strains in the respiratory tract having bacteriostatic properties against common pathogens., Methods: The oropharyngeal microbiota of five healthy children aged 4-6 years were collected and α-hemolytic bacteria screened on 15% sheep blood agar. Bacteriostatic effects of the isolated α-hemolytic bacteria on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Streptococcus pyogenes were evaluated by the Oxford cup method. Antagonistic strains were identified by mass spectrometry, and the16S rDNAs were sequenced, and their best bacteriostatic concentrations and antagonistic spectra for Klebsiella pneumoniae, Proteus vulgaris, Enterobacter cloacae, Acinetobacter Baumanii, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Streptococcus pyogenes were evaluated., Results: Of 300 isolated α-hemolytic bacterial clones, four exhibited bacteriostatic activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Streptococcus pyogenes. Mass spectrometric analyses revealed that two of them were Streptococcus mitis and two others were Streptococcus parasanguinis strains. Further tests showed that all 4 antagonistic strains also had bacteriostatic effects on Klebsiella pneumoniae, Proteus vulgaris, Enterobacter cloacae, and Acinetobacter Baumanii, and the mode of action was not mediated by lactic acid production., Conclusion: Four antagonistic Streptococcus strains derived from oropharyngeal microbiotas showed bacteriostatic effects on pathogens and may be involved in pharyngeal microbiome homeostasis., (© 2019 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

Hemodialysis patients are particularly vulnerable to Staphylococcus aureus infection, with the vascular access serving as the site of entry for this formidable pathogen. Patients with arteriovenous grafts (AVGs) and tunneled-cuffed catheters (TCCs) are at elevated risk of S. aureus infection. In this study, we investigated the correlation between the clinical characteristics of S. aureus vascular access infection (VAI), molecular profiles, and the biofilm formation abilities of clinical isolates of S. aureus. We collected samples of methicillin-resistant S. aureus (MRSA), methicillin-sensitive S. aureus (MSSA), and methicillin-sensitive S. argenteus (MSSAg) from patients with S. aureus VAI and patients with other infections. The molecular profiles of the clinical isolates were determined using disk diffusion testing and molecular typing. The biofilm formation ability was determined by microtiter plate assay. In total, 63 S. aureus and 10 S. argenteus isolates were identified: 40 MRSA, 23 MSSA, and ten MSSAg. MRSA was highly prevalent (77.8%) in TCC isolates and was multidrug resistant. Of the 40 MRSA isolates, ST239-SCCmec III was the predominant clone. SCCmec type IV was the predominant type (35%) in isolates from AVGs, while SCCmec type III was prevalent in TCC infection and showed significantly higher biofilm formation ability than types IV and V. In dialysis VAI by S. aureus, patients with TCC were more often infected with MRSA than patients with AVG, and MRSA in TCC-VAI was predominantly SCCmec type III, which had the strongest drug resistance and biofilm formation ability., (© 2019 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

Recultured Lactobacillus plantarum 299v-like strains were tested regarding antibiotic susceptibility, and no decrease was detected. Antibiotics are frequently used to treat patients in intensive care units (ICUs) and are associated with a significant risk of selection of resistant bacterial strains. In particular, it is possible that genetic transfer of antibiotic resistance to the resident gastrointestinal flora, as well as to administered probiotics, may be increased in the ICU setting. The aim of the present investigation was to detect possible changes in antimicrobial susceptibility in reisolates of the probiotic strain Lactobacillus plantarum 299v (Lp299v) given to antibiotic treated, critically ill patients. Lp299v-like strains were identified in cultures of biopsies and fecal samples from 32 patients given the probiotic strain enterally in two previous ICU studies. The patients received a variety of antibiotics. Isolates with the same genomic RAPD profile (RAPD-type) as Lp299v were obtained to enable monitoring of antibiotic susceptibility by E-tests. Forty-two isolates, collected throughout the course of illness, were tested against 22 different antibiotics. No obvious decrease in susceptibility was found for 21 of the tested antibiotics. There was a tendency toward decreased susceptibility to ampicillin. The stable antibiotic susceptibility profiles of the Lp299v-like isolates studied here suggests this probiotic is less likely to acquire resistance when administered to critically ill patients treated with broad-spectrum antibiotics., (© 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

This study aimed to perform in vitro antiparasitic and antimicrobial tests with the essential oil (EO) of Schinus terebinthifolius against of fish and shrimp. The chemical composition of the EO of S. terebinthifolius was determined by gas chromatography. For the antiparasitic test, the protozoan Epistylis sp. obtained from parasitized Oreochromis niloticus was used, and exposed to different concentrations of EO (2%, 1%, 0.5%, 0.25%), and control with 1% grain alcohol. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) test with EO of S. terebinthifolius evaluated the antimicrobial potential, with serial dilutions starting at 2% and control with 1% grain alcohol, using the strains of Aeromonas hydrophila (2.2 × 108 CFU mL−1), Edwardsiella tarda, Vibrio parahaemolyticus, V. harveyi, and V. alginolyticus (2.0 × 108 CFU mL−1). Chemical analysis revealed that the major EO compounds of S. terebinthifolius were δ‐3‐Carene (56.00%) and α‐Pinene (16.89%). In the antiparasitic test, the concentration of 2% EO showed 100% efficacy against Epistylis sp. within 5 min. In the antimicrobial tests, the concentration of 2% EO was effective against all bacteria tested. The EO of S. terebinthifolius demonstrated antiparasitic and antimicrobial activity at a concentration of 2%, standing out as an alternative to conventional antibiotics. [ABSTRACT FROM AUTHOR]

Accurate and rapid detection of carbapenemases and identification of their types in Enterobacteriaceae are both still major challenges for clinical laboratories in attempting to prevent the intrusion and transmission of carbapenemase-producing Enterobacteriaceae. This study aimed to evaluate the performance of the MASTDISCS combi Carba plus disc system in identification of different carbapenemase types, including OXA-48-type carbapenemase, for which no specific enzyme inhibitors have so far been available. The simple disc system discriminates carbapenemases, including OXA-48-types exhibiting low carbapenem minimum inhibitory concentrations, by targeting Enterobacteriaceae isolates with a EUCAST meropenem screening cut-off of ≥0.25 mg/L., (© 2017 The Societies and John Wiley & Sons Australia, Ltd.)

A promising means of rapid screening of extended-spectrum-β-lactamase (ESBL), AmpC β-lactamase, and co-production of ESBL and AmpC that combines resazurin chromogenic agar (RCA) with a combined disc method is here reported. Cefpodoxime (CPD) discs with and without clavulanic acid (CA), cloxacillin (CX) and CA+CX were evaluated against 86 molecularly confirmed β-lactamase-producing Enterobacteriaceae, including 15 ESBLs, 32 AmpCs, nine co-producers of ESBL and AmpC and 30 carbapenemase producers. The CA and CX synergy test successfully detected all ESBL producers (100% sensitivity and 98.6% specificity) and all AmpC producers (100% sensitivity and 96.36% specificity). This assay also performed well in screening for co-existence of ESBL and AmpC (88.89% sensitivity and 100% specificity). The RCA assay is simple and inexpensive and provides results within 7 hr. It can be performed in any microbiological laboratory, in particular, in geographic regions in which ESBL, AmpC or co-β-lactamase-producing Enterobacteriaceae are endemic., (© 2017 The Societies and John Wiley & Sons Australia, Ltd.)

Background: With markedly increased antibiotic resistance and unsatisfactory efficacies of common empiric eradication regimens in the mainland of China, tailored therapy may be the best choice to achieve good efficacy. This study compared the eradication rates, safety, and compliance of tailored therapy to those of triple therapy plus bismuth and concomitant therapy in the naïve patients with Helicobacter pylori infection., Materials and Methods: Between September 2013 and April 2014, 1050 patients with H. pylori infection at three tertiary hospitals were randomly assigned to 10-day treatment with tailored, triple plus bismuth, or concomitant regimens. In tailored therapy, medications were adjusted according to clarithromycin sensitivity and cytochrome P450 isoenzyme 2C19 genotype. The antimicrobial susceptibility testing (E test) was performed. Eradication status was assessed 4-12 weeks after treatment., Results: The eradication rate was significantly higher in tailored group than in triple plus bismuth and concomitant groups in both intention-to-treat (88.7 vs 77.4 vs 78.3%, p < .001) and per-protocol (93.3 vs 87.0 vs 87.4%, p = .021) analyses in a setting with high antibiotic resistance (clarithromycin 48.8%, metronidazole 65.7%, and dual resistance 35.3%). Significantly, fewer adverse effects occurred in tailored group than in concomitant group (22.0 vs 31.7%, p = .018). The eradication rates of dual clarithromycin and metronidazole resistance, isolated clarithromycin resistance, isolated metronidazole resistance, and dual susceptible were 78.7, 82.4, 94.8, and 94.4% in triple therapy plus bismuth and 75.9, 87.2, 92.9, and 95.2% in concomitant therapy, respectively., Conclusions: First-line tailored therapy achieves significantly higher eradication rates and fewer side effects, compared to triple therapy plus bismuth and concomitant therapy in a setting with high rates of clarithromycin and metronidazole resistance., (© 2015 John Wiley & Sons Ltd.)

Antibiotic-loaded acrylic bone cement has been frequently used as an infection prophylaxis or antibiotic-loaded spacer in infected arthroplasty. In addition, daptomycin has been used recently against broad spectrum Gram-positive organisms. The goal of this in vitro study is to investigate the bacteriacidal and mechanical properties of daptomycin-incorporated polymethylmethacrylate (PMMA) bone cement and evaluate its feasibility for clinical use. Daptomycin (0.5, 1, or 2 g) was premixed with 40 g of PMMA bone cement powder before curing. The mechanical properties of the daptomycin-loaded acrylic bone cement (DLABC) were estimated following standard guidance, and the release profile and kinetics of daptomycin from PMMA were analyzed. The antimicrobial efficacy of DLABC was determined with a zone of inhibition (ZOI) assay against Staphylococcus aureus, Staphylococcus epidermis, Enterococcus faecalis, and Enterococcus faecium, respectively. The results showed that the compressive strength, of PMMA bone cement, which was higher than 100 MPa in all groups, was sufficient according to ISO 5833 after incorporation of daptomycin. The encapsulated daptomycin was released for 2 weeks with a 9.59 ± 0.85%, 15.25 ± 0.69%, and 20.64 ± 20.33% released percentage on the first day in the low, mid, and high groups, respectively. According to the calculated release kinetics, incorporated daptomycin should be 3.3 times the original dose to double its release. Although all recipes of DLABC had a microbial inhibitory effect, the effect with a higher encapsulated amount of daptomycin was more significant. Therefore, we believe that daptomycin can be locally delivered from PMMA bone cement at the surgical site as a prophylactic or treatment for osteomyelitis against Gram-positive organisms with intact cement function., (Copyright © 2013 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.)

The aim of the present paper was to compare different methods for detecting methicillin resistance in Staphylococcus aureus. Among the isolates analyzed, 52 belonged to MRSA international lineages commonly detected in the American continent and 14 to sporadic MRSA clones. Both 30 microg-cefoxitin disk and PBP2a had 100% sensibility/specificity when the low-level heterogeneous isolates were tested and, thus, are highly recommended.

Bio‐active ethylcellulose (EC) polymeric films have been obtained by incorporating curcumin (curc) and Ag(I)‐based compounds, known for their antioxidant and antimicrobial activity, respectively, within the polymeric matrix. The recently reported Ag(I) coordination polymer, in both its structural forms (α‐[(bpy)Ag(OTf)]∞ and β‐{[(bpy)Ag][OTf]}∞), and the [(bpy)Ag(OTf)]∞‐curc polymeric co‐crystal (bpy=2,2′‐bipyridine; OTf=trifluoromethanesulfonate) have been selected as Ag(I) species. The hybrid composite films have been prepared through the simple solvent casting method and characterized through Powder X‐Ray Diffraction (PXRD), Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscope (SEM), UV‐vis spectroscopy. The deep investigation of the film samples highlighted the non‐inert behaviour of EC towards these specific active ingredients. Antimicrobial tests showed that EC films embedding the Ag(I)‐based compounds present good antimicrobial performance, in particular against Staphylococcus aureus, used as a model of Gram‐positive bacteria. In addition, Silver migration tests, performed on the Ag(I)‐incorporating EC films, evidenced low values of silver release particularly in the case of the EC films incorporating [(bpy)Ag(OTf)]∞‐curc. [ABSTRACT FROM AUTHOR]

Polymeric films are used in numerous applications in the biomedical area. The incorporation of antimicrobial agents into these materials can prevent their surface from acting as a source of contamination of viruses and bacteria. In the present work, cinnamon and eucalyptus essential oils were incorporated into low‐density polyethylene (LDPE) by melt extrusion, as confirmed by Fourier transform infrared spectroscopy. For the success of incorporation, talc was used as an oil carrier and fixer. Despite high processing temperatures used (up to 175°C), the oleophilic character of talc was able to minimize oil losses, as proven by thermogravimetry. Good thermal and mechanical properties evaluated by differential scanning calorimetry and tensile tests were confirmed. In addition, antimicrobial tests confirmed film activity against virus SARS‐CoV‐2 and bacteria Staphylococcus aureus and Escherichia coli. LDPE films incorporated with both oils showed significant antiviral properties against SARS‐CoV‐2, with viral titers reduction between 95.89% and 100%. Cinnamon oil showed more efficient antibacterial properties than eucalyptus oil, with relative bacterial growths of films next to zero (0.37% for E. coli and 2.07% for S. aureus). To the best of our knowledge, no previous work has developed plastic films incorporated with essential oils with confirmed antiviral properties against SARS‐CoV‐2. [ABSTRACT FROM AUTHOR]

This article focused on the preparation of Cu, Co (II)‐containing linoleic‐based poly(ester amide) resin and studied their use as new binders for paint formulation. The metal‐containing LPEA was carried out by in situ condensation polymerization reaction between hydroxyethyl linoleic fatty amide diol (HELA), phthalic anhydride (PA), and Cu, Co acetate. The structure of the prepared resins was confirmed by FTIR and 1H NMR spectral studies. Physicochemical, thermal analysis (TGA), surface morphology (SEM), and elemental composition (EDX) were studied by standard methods. The physicomechanical, antimicrobial, and corrosion/chemical resistance performance tests were also conducted to evaluate their coating properties. These studies revealed that (i) the incorporation of Cu, Co (II) has a significant influence on structural and physicochemical aspects. The paint formulation based on Cu, Co (II) containing LPEA showed very good results according to the corrosion resistant test evalution. (iii) Antimicrobial tests of all prepared resins were performed by agar diffusion method against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Klebsiella pneumonia, and pathogenic fungal strain using standard controlled medication, ciprofloxacin/fluconazole for the comparison. (iv) Cu, Co (II) containing LPEA serve as novel binders and promising candidates for use as binders for protective coating material. [ABSTRACT FROM AUTHOR]

Molybdenum trioxide (MoO3) and zinc oxide (ZnO) were incorporated into the poly(butylene adipate‐co‐terephthalate) (PBAT) matrix using casting method to obtain packing films for food transportation with outstanding properties and no formation of microplastics. Consequently, these films were evaluated using Fourier transform infrared spectroscopy, time domain and carbon‐13 nuclear magnetic resonance, x‐ray diffraction, contact angle measurement, and thermogravimetric analysis. The light barrier properties of the films were analyzed using transmittance mode in UV–VIS–NIR regions and the contact angle of composite films exhibited greater hydrophilicity compared to the pure polymer films. Regardless of the concentration, the fillers did not significantly modify the degradation onset temperature and the temperature of maximum degradation rate. However, ZnO caused a new thermal degradation event (around 330°C) that was not observed in the other films, possibly due to the second crystallization process. Composite films filled with 0.3% ZnO, 0.3% and 0.5% MoO3 showed greater molecular homogeneity than the pure polymer matrix, with the PBAT/MoO3 films demonstrating even greater homogeneity than PBAT/ZnO films; this response presumably comes from the satisfactory intermolecular interaction or adequate dispersion and distribution of the particles. The addition of 0.5% MoO3 in the matrix influenced the PBAT film, resulting in amorphous materials with the highest molecular mobility and opacity. Besides, in view of antimicrobial tests, all nanocomposites showed potential bacteriostatic activity. So, it can be conveniently used for food transportation and may avoid microplastic formation, after been discarded. [ABSTRACT FROM AUTHOR]

Biofilms are communities of bacterial cells encased in a self‐produced polymeric matrix that exhibit high tolerance toward environmental stress. Despite the plethora of research on biofilms, most P. aeruginosa biofilm models are cultured on a solid–liquid interface, and the longitudinal growth characteristics of P. aeruginosa biofilm are unclear. This study demonstrates the real‐time and noninvasive monitoring of biofilm growth using a novel dual‐chamber microfluidic device integrated with electrochemical detection capabilities to monitor pyocyanin (PYO). The growth of P. aeruginosa biofilms on the air–liquid interface (ALI) was monitored over 48 h, and its antibiotic susceptibility to 6 h exposure of 50, 400, and 1600 µg/ml of ciprofloxacin solutions was analyzed. The biofilm was treated directly on its surface and indirectly from the substratum by delivering the CIP solution to the top or bottom chamber of the microfluidic device. Results showed that P. aeruginosa biofilm developed on ALI produces PYO continuously, with the PYO production rate varying longitudinally and peak production observed between 24 and 30 h. In addition, this current study shows that the amount of PYO produced by the ALI biofilm is proportional to its viable cell numbers, which has not been previously demonstrated. Biofilm treated with ciprofloxacin solution above 400 µg/ml showed significant PYO reduction, with biofilms being killed more effectively when treatment was applied to their surfaces. The electrochemical measurement results have been verified with colony‐forming unit count results, and the strong correlation between the PYO electrical signal and the viable cell number highlights the usefulness of this approach for fast and low‐cost ALI biofilm study and antimicrobial tests. [ABSTRACT FROM AUTHOR]

This study aimed to turn classically brittle zein films into flexible antimicrobial ones by the use of lactic (LA), malic (MA) and tartaric acids (TA). The most effective plasticizer was LA (400% elongation at break [EB] at 4%), while MA (189% EB at 4.5%) and TA (68% EB at 5%) showed moderate and limited plasticizing effects, respectively. The LA‐ and MA‐loaded films maintained their flexibility during 30‐day storage at 4°C or 25°C. Fourier transform infrared (FTIR) analysis suggested that the plasticization of LA and MA could be related to secondary structural changes in zein such as increased α‐helix and random coils (mainly by MA) and spaced/modified intermolecular (only by LA) and intramolecular (mainly by MA) β‐sheets. Atomic force and scanning electron microscopy showed that LA and MA gave more homogenous and smoother films than TA. Films with LA showed the highest water vapour permeability followed by those of control, MA‐ and TA‐loaded films. Films with 3%–4% LA or MA formed clear zones on Listeria innocua and Klebsiella pneumonia, but only films with LA formed clear zones on Escherichia coli. All OA‐loaded films gave unclear zones on Staphylococcus aureus in disc‐diffusion tests, but this bacterium was inactivated rapidly in antimicrobial tests based on surface inoculation tests. LA is the best OA to develop flexible antimicrobial films from zein, an industrial by‐product that films could not have been utilized as a widespread packaging material due to their brittleness. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the chemical composition of the Zataria multiflora Bioss and Mentha longifolia essential oils (ZEO and MEO) and evaluate their antibacterial efficiency, alone and in combination with nisin and acid acetic, against Escherichia coli O157: H7 and Staphylococcus aureus. The results of antimicrobial tests showed that plant EOs, nisin, and acetic acid have good bacteriostatic and bactericidal properties. In the checkerboard test, nisin had synergistic interaction with both ZEO and MEO against S. aureus and E. coli (FIC index <0.5). Also, there was a synergistic interaction between ZEO and MEO. Based on the GC‐MS analysis, the main constituents of ZEO were carvacrol (49.61%), thymol (14.31%), and p‐cymene (5.23%). Besides 1,8‐cineole (18.46%), pulegone (14.82%), and piperitone (12.12%) were the most detected substance of MEO. The combination of nisin with the EOs can exert an inhibitory effect on bacterial growth in food. Novelty impact statement: In this present study, the synergistic effect of the Zataria multiflora Bioss and Mentha longifolia essential oils (EOs) in combination with nisin and acetic acid was investigated for the first time. The interaction of EOs with nisin and acetic acid against Escherichia coli O157: H7 and Staphylococcus aureus was synergistic and additive, respectively. The two studied EOs also had a synergistic interaction in the combined use. [ABSTRACT FROM AUTHOR]

Tantalum (Ta) and its application in biomaterials has been attracting more and more attention recently. It can be considered as a material for hard tissue implants. This study focuses on antimicrobial and surface characterization of micro‐arc oxidized (MAO) nanocrystalline Ta compared with its microcrystalline equivalent. For the purposes of the investigation, x‐ray diffractometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), wetting analysis, optical profilometry, corrosion resistance measurement, and antimicrobial tests were performed. Nanocrystalline Ta was fabricated using high‐energy ball milling (HEBM) and pulse plasma sintering (PPS). The MAO process done at 250 V results in the formation of a porous oxide surface. An XRD analysis confirmed the presence of a Ta2O5 oxide layer. Based on the SEM pictures, the obtained oxide layer was approximately 3–4 μm thick for nanocrystalline Ta substrate. For microcrystalline Ta, the oxide layer was thinner, in the range of 0.3–0.6 μm. The analysis of polarization curves showed a significant improvement of corrosion resistance for MAO nanocrystalline Ta (2.62 × 10−8 A/cm2) versus not oxidized nanocrystalline Ta (1.20 × 10−5 A/cm2). The surface roughness of MAO nanocrystalline Ta proved to be several times higher than that of unoxidized Ta. Wetting analysis showed that the oxide layer on the nanocrystalline substrate is hydrophilic. This research provides detailed information about MAO microcrystalline and MAO nanocrystalline Ta antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. A significant decrease of S. aureus for MAO nanocrystalline Ta (control 10,435 ± 981 vs. sample 3,453 ± 130) was noticed. No significant difference was noticed for MAO microcrystalline and nanocrystalline Ta tested for P. aeruginosa. [ABSTRACT FROM AUTHOR]

The aim of this study was to fabricate antimicrobial calcium‐alginate‐based films containing the self‐microemulsifying thyme essential oil (TEO) formulations using Tween 80 as the surfactant, and acetic (AA) or propionic (PA) acids as the cosurfactants. A Ca‐alginate film containing nano‐emulsified TEO as well as a neat Ca‐alginate film were considered as the controls. The scanning electron microscopy micrographs showed a highly porous texture for SME films, which resulted in an increase in water vapor permeability and water absorption capacity of these films. The SME films released the TEO completely within 155 min and inhibited the growth of S. aureus and E. coli in in vitro antimicrobial tests. The population of S. aureus and E. coli reduced significantly in ground beef covered with SME films. The results of this study showed that self‐microemulsifying TEO films could effectively increase the shelf life of ground beef by controlling its microbial population. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the antimicrobial, toxicity and cleaning effectiveness of ethylenediaminetetraacetic acid (EDTA) and maleic acid (MA) alone and combined with cetrimide (CTR). Methodology: Cytotoxic and genotoxic effects were assessed on Chinese hamster cells V79 using the MTT, clonogenic and micronucleus assays, respectively. The bacterial inhibitory and bactericidal concentrations (MIC and MBC, respectively) were determined on a strain of Enterococcus faecalis. Antimicrobial tests were performed on a biofilm model after treatment with the chelating agents by using a biofilm eradication concentration (MBEC) and confocal laser scanning microscope (CLSM) assays. Quantification of cell biomass and percentage of live and dead cells in the biomass were assessed for each group. The percentage reduction of accumulated hard‐tissue debris (AHTD) after root canal preparation and final irrigation protocols was evaluated by micro‐CT. Statistical tests of one‐way analysis of variance (anova), Bonferroni test, Kruskal–Wallis test, Dunn's multiple comparison test and Wilcoxon matched‐pairs signed‐rank tests were used. Results: Cetrimide alone as well as in combination with EDTA and MA at dilutions of 1/10 and 1/100 was significantly more toxic as compared to untreated controls (P < 0.001). All tested mixtures were nontoxic at a dilution of 1/1000. EDTA retained a weak inhibitory and bactericidal effect against planktonic cells, whilst MA inhibited cells growth and killed 99.9% of the cells when diluted. CTR revealed the most prominent effect, being inhibitory and bactericidal, also when diluted. Cetrimide alone or combined with EDTA was able to remove, respectively, 40% (P < 0.01) and 60% (P < 0.001) of the entire biomass after 1 min. Conversely, MA alone and in combination with CTR did not have a significant effect on biomass reduction. After final irrigation, the AHTD volume was significantly decreased in all groups (P < 0.05). EDTA + CTR and MA + CTR were associated with a significant reduction in the percentage of AHTD on the entire root canal compared to the same solutions without surfactant. Conclusions: 7% MA was less cytotoxic in comparison with 17% EDTA. The addition of cetrimide to EDTA and MA removed accumulated hard‐tissue debris effectively from the canal walls and increased their antimicrobial activity when compared to the same solutions without detergents. [ABSTRACT FROM AUTHOR]

Poly(lactic acid) (PLA) is a versatile, bioabsorbable, and biodegradable polymer with excellent biocompatibility and ability to incorporate a great variety of active agents. Silver sulfadiazine (SDZ) is an antibiotic used to control bacterial infection in external wounds. Aiming to combine the properties of PLA and SDZ, hydrotalcite ([Mg–Al]‐LDH) was used as a host matrix to obtain an antimicrobial system efficient in delivering SDZ from electrospun PLA scaffolds intended for wound skin healing. The structural reconstruction method was successfully applied to intercalate silver sulfadiazine in the [Mg–Al]‐LDH, as evidenced by X‐ray diffraction and thermogravimetric analyses. Observations by scanning electron microscopy revealed a good distribution of SDZ‐[Mg–Al]‐LDH within the PLA scaffold. Kinetics studies revealed a slow release of SDZ from the PLA scaffold due to the intercalation in the [Mg–Al]‐LDH. In vitro antimicrobial tests indicated a significant inhibitory effect of SDZ‐[Mg–Al]‐LDH against Escherichia coli and Staphylococcus aureus. This antibacterial activity was sustained in the 2.5‐wt% SDZ‐[Mg–Al]‐LDH–loaded PLA nanofibers, which also displayed excellent biocompatibility towards human cells. The multifunctionality of the PLA/SDZ‐[Mg–Al]‐LDH scaffold reported here is of great significance for various transdermal applications. [ABSTRACT FROM AUTHOR]

2,4‐Thiazolidinedione derivatives represent nitrogen‐containing heterocyclic compounds utilized in type 2 diabetes mellitus management. Recent advances in medicinal chemistry have unveiled diverse therapeutic potentials and structural modifications of these derivatives. This review delves into novel TZD derivatives, encompassing their synthesis, structure‐activity relationships, and pharmacokinetic profiles. Various therapeutic potentials of TZDs are explored, including anticancer, antimicrobial, anti‐inflammatory, antioxidant, anticonvulsant, antihyperlipidemic, anticorrosive, and antitubercular activities. Additionally, it addresses mitigating side effects associated with marketed TZD derivatives such as weight gain, oedema, fractures, and congestive heart failure in type 2 diabetes mellitus management. The review elaborates on in vivo, in vitro, and ex vivo studies supporting different biological activities, alongside predicting ADME and drug‐likeness properties of TZDs. Computational studies are also integrated to elucidate binding modes and affinities of novel TZD derivatives. Furthermore, a plethora of novel TZD derivatives with varied and enhanced therapeutic potentials are presented, warranting further evaluation of their biological activities. [ABSTRACT FROM AUTHOR]

Biological Nitrification Inhibition (BNI) encompasses primarily NH4+‐induced release of secondary metabolites to impede the rhizospheric nitrifying microbes from performing nitrification. The intermediate wheatgrass Thinopyrum intermedium (Kernza®) is known for exuding several nitrification inhibition traits, but its BNI potential has not yet been identified. We hypothesized Kernza® to evince BNI potential through the presence and release of multiple BNI metabolites. The presence of BNI metabolites in the biomass of Kernza® and annual winter wheat (Triticum aestivum) and in the root exudates of hydroponically grown Kernza®, were fingerprinted using HPLC‐DAD and GC–MS/MS analyses. Growth bioassays involving ammonia‐oxidizing bacteria (AOB) and archaea (AOA) strains were conducted to assess the influence of the crude root metabolome of Kernza® and selected metabolites on nitrification. In most instances, significant concentrations of various metabolites with BNI potential were observed in the leaf and root biomass of Kernza® compared to annual winter wheat. Furthermore, NH4+ nutrition triggered the exudation of various phenolic BNI metabolites. Crude root exudates of Kernza® inhibited multiple AOB strains and completely inhibited N. viennensis. Vanillic acid, caffeic acid, vanillin, and phenylalanine suppressed the growth of all AOB and AOA strains tested, and reduced soil nitrification, while syringic acid and 2,6‐dihydroxybenzoic acid were ineffective. We demonstrated the considerable role of the Kernza® metabolome in suppressing nitrification through active exudation of multiple nitrification inhibitors. [ABSTRACT FROM AUTHOR]

Background: The minimal inhibitory concentration (MIC) of an aqueous extract of Lippia citriodora with reported functional properties (PLX®) was determined on two strains of Escherichia coli (E. coli) belonging to serogroups commonly associated with foodborne illnesses (E. coli O157:H7 ATCC 700728 and E. coli O111 isolate 172) in vegetable products and two control strains for antimicrobial tests assays (E. coli ATCC 25922 and Enterococcus–En. faecalis ATCC 29212). Results: Mean MIC values at standard pH (7.4) in broth for the E. coli strains tested ranged from 4,444 µg/ml (35ºC) to 1,250 µg/ml (10ºC) and to 182 µg/ml (4ºC). At pH 5.5, conditions resembling those of melon juice, MIC was about 2 times higher at 35 and 10ºC compared with 4ºC. The MIC of En. faecalis was similar or slightly lower than those of E. coli at the conditions tested. In melon juice fortified with PLX® (2,500 µg/ml, maximum sensorial acceptable limit), the three strains of E. coli maintained their viability although none showed growth potential after 4 days at 4ºC. Conclusions: PLX® could be added to melon juice to control E. coli O157:H7 and E. coli O111 during refrigerated storage, reducing the risk of microbiological contamination in this food. [ABSTRACT FROM AUTHOR]

Polyethersulfone (PES) has been widely used in membrane technology and used to purify water in water treatments application or as a dialyzer to purify blood in hemodialysis. In this work, PES was chemically modified by separately grafting two biomolecules, 4‐aminobenzenesulfonamide (ABS), and 4‐amino‐N‐(5‐methylisoxazol‐3‐yl)benzenesulfonamide (AMBS), on PES backbone, and these modified membranes were blended to unmodified PES, in 1:1 ratio, in order to obtain PES‐b‐PES‐ABS and PES‐b‐PES‐AMBS membranes. The first aim of this study is to measure the anticoagulant properties of the modified membrane by measuring the activated partial thromboplastin time (APTT) and prothrombin time (PT). The second aim of the study is to evaluate the antifouling properties of the modified PES membranes by examining its antimicrobial activity against two Gram‐negative bacteria, which are Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli); two Gram‐positive bacteria, which are Bacillus subtilis (B. subtilis) and Staphylococcus aureus (S. aureus); and a fungus, which is Candida albicans (C. albicans). The results showed that grafting of ABS and AMBS improved overall the hydrophilicity properties of the modified PES membranes. PES‐b‐PES‐ABS membranes showed better anticoagulant properties with 13 seconds for PT and 38 seconds for APPT, in comparison with the control sample (pure plasma), which showed 12 seconds for PT and 30 seconds for APPT. For antimicrobial tests, both PES‐b‐PES‐ABS and PES‐b‐PES‐AMBS membranes did not show any antibacterial activity, but when zinc oxide (ZnO) nanoparticles were added to the modified PES membranes in concentrations between 3% to 5% w/w, PES‐b‐PES‐ABS‐ZnO (M‐4 and M‐5), and PES‐b‐PES‐AMBS‐ZnO (M‐8 and M‐9) nanocomposite membranes showed antibacterial activity against P. aeruginosa and S. aureus. [ABSTRACT FROM AUTHOR]

The microbial resistance of fungi and bacteria is currently considered a major public health problem. Esters derived from cinnamic acid have a broad spectrum of pharmacological properties that include antimicrobial activity. In this study, a collection of structurally related 4-chlorocinnamic acid esters was prepared using Fischer esterification reactions, alkyl or aryl halide esterification, and Mitsunobu and Steglich reactions. All of the esters were submitted to antimicrobial tests against strains of the species Candida albicans, Candida glabrata, Candida krusei, Candida guilliermondii, Pseudomonas aeruginosa, and Staphylococcus aureus. The compounds also were subjected to molecular docking study with the enzyme 14α-demethylase. Twelve esters derived from 4-chlorocinnamic acid were obtained, with yields varying from 26.3% to 97.6%, three of which were unpublished. The ester methyl 4-chlorocinnamate (1) presented activity against S. aureus at the highest concentration tested. In the antifungal evaluation, all of the esters were bioactive, but methoxyethyl 4-chlorocinnamate (4) and perillyl 4-chlorocinnamate (11) were the most potent (MIC = 0.13 and 0.024 μmol/mL, respectively). The data of molecular docking suggested that all the compounds present good affinity towards the active site related to antifungal activity. Therefore, the esters tested may be inhibitors of the enzyme 14α-demethylase. In addition, the results demonstrate that substituents of short alkyl chains with presence of heteroatom, such as oxygen, or those with a perillyl type terpenic substructure promote better antifungal profiles. [ABSTRACT FROM AUTHOR]

The involvement of multiple antibiotic‐resistant gastrointestinal pathogens in diarrhea aggravates the disease condition uncontrollably. The current study aimed to find and develop a suitable formulation utilizing multiple natural components from known plant sources to augment the current therapeutic outcomes. The hydroethanolic extraction method was applied through boiling and fermentation on ancient observation‐based efficacious plant parts for developing the antidiarrheal polyherbal formulation AP‐01. An animal study model of diarrhea was used to evaluate the safety and efficacy of the formulation. The formulation was tested in vitro on four different multiple antibiotic‐resistant gastrointestinal pathogens collected from the national repository. The formulation depicted no cytotoxicity on normal gut cells and was efficacious at 10 ml/kg single dose in relieving symptoms of diarrhea by 79.71%, compared with the standard drug showing a reduction of symptoms by 83.01%. AP‐01 exhibited delayed gastric motility. The symptoms of diarrhea ceased to occur within 320.66 ± 5.05 minutes with AP‐01, whereas the standard drug took 308 ± 6.63 minutes. AP‐01 was found successful at a viable dosage regimen of 75 μl/ml v/v to 100 μl/ml v/v in inhibiting the growth of different pathogens from the Enterobacteriaceae family possessing resistance against several classes of antibiotics in culture media. Chemical analysis revealed different alkaloids, flavonoids, and polyphenols that probably work in unison through multiple modes of action to arrest diarrhea and inhibit pathogens simultaneously. These promising results shown by AP‐01 should evoke an effort to dive deep into research and development for better therapeutic formulations for infectious diarrhea by harvesting nature's arsenal. [ABSTRACT FROM AUTHOR]

This systematic review investigates the antibacterial effects of silver nanoparticles (AgNPs) on polymicrobial biofilms in endodontics, emphasizing their potential enhancement of traditional treatment methods. Recognizing the limitations of current endodontic disinfectants in fully eradicating complex biofilms, this study focuses on the synergistic potential of AgNPs to improve antimicrobial efficacy. Utilizing a systematic approach based on PRISMA guidelines, the review draws on studies from databases like PubMed, Web of Science, and SCOPUS up to 2024. The included research specifically examines the role of AgNPs in various endodontic applications against resilient biofilms, adhering to strict inclusion criteria that demand clear methodology and measurable outcomes. The results suggest that AgNPs can significantly augment the biofilm disruption capabilities of conventional antimicrobials, potentially due to their ability to modify the biofilm matrix and enhance agent penetration. However, the effectiveness varies depending on the nanoparticle concentration and application technique, indicating a need for further optimized studies. In conclusion, while AgNPs show promise in enhancing endodontic antimicrobial protocols, additional in vivo research is necessary to establish standardized, effective, and safe clinical applications. The review highlights the complex interactions between nanoparticle properties and biofilm biology, underscoring the importance of further investigation in this area. [ABSTRACT FROM AUTHOR]

In this transformative study, machine learning (ML) and t‐distributed stochastic neighbor embedding (t‐SNE) are employed to interpret intricate patterns in colorimetric images of cold atmospheric plasma (CAP)‐treated water. The focus is on CAP's therapeutic potential, particularly its ability to generate reactive oxygen and nitrogen species (RONS) that play a crucial role in antimicrobial activity. RGB, HSV, LAB, YCrCb, and grayscale color spaces are extracted from the colorimetric expression of oxidative stress induced by RONS, and these features are used for unsupervised ML, employing density‐based spatial clustering of applications with noise (DBSCAN). The DBSCAN model's performance is evaluated using homogeneity, completeness, and adjusted rand index with a predictive data distribution graph. The best results are achieved with 3,3′,5,5′‐tetramethylbenzidine–potassium iodide colorimetric assay solution immediately after plasma treatment, with values of 0.894, 0.996, and 0.826. t‐SNE is further conducted for the best‐case scenario to evaluate the clustering efficacy and find the best combination of features to better present the results. Correspondingly, t‐SNE enhances clustering efficacy and adeptly handles challenging points. The approach pioneers dynamic and comprehensive solutions, showcasing ML's precision and t‐SNE's transformative visualization. Through this innovative fusion, complex relationships are unraveled, marking a paradigm shift in biomedical analytical methodologies. [ABSTRACT FROM AUTHOR]

Light‐assisted 3D printing technology, which uses a light source to solidify a photopolymerizable prepolymer solution, has shown great potential in the development of antibacterial hydrogels with high‐resolution, specific features and functionalities. 3D‐printed hydrogels with customized structures and antibacterial functions are widely used in tissue engineering, regenerative medicine, wound healing, and implants to advance the modeling and treatment of diseases. In the current review, an overview of light‐assisted 3D printing technologies is first provided for the development of antibacterial hydrogels. Novel strategies involving the integration of inorganic nanomaterials, antibiotics, and functional polymers into 3D‐printed hydrogels for the enhancement of antibacterial effects are then discussed. Finally, the perspective of advanced design using artificial intelligence and machine learning is proposed, providing a comprehensive yet succinct examination of 3D‐printed hydrogels for antibacterial purposes. [ABSTRACT FROM AUTHOR]

In recent years, development of biopolymeric nanofibers as an active biodegradable packaging system has attracted specific attention. The objective of this research was to develop zein‐based electrospun nanofibers (NFs) incorporated with geraniol‐loaded nanoliposomes (G‐loaded NLPs). Geraniol was encapsulated into NLPs with an efficiency of 79.23%. The particle size and zeta potential of G‐loaded NLPs were 121.50 nm and −38.30 mV, respectively. The successful loading of geraniol in the NLPs was approved by Fourier transform infrared (FT‐IR) spectroscopy. The liposomal vesicles showed spherical shapes. G‐loaded NLPs were added in the zein‐based electrospun NFs at three different concentrations (0.25, 0.5, and 1%w/v). All NFs samples exhibited fibrillar structure. The increase of NLPs concentration enhanced the thermal stability of the NFs. However, the crystalline structure of zein NFs did not change by the addition of G‐loaded NLPs. The highest surface hydrophobicity was related to the NFs containing 1% G‐loaded NLPs. The mechanical parameters of NFs depend on the concentration of NLPs. The NFs incorporated with G‐loaded NLPs showed inhibition activity against four foodborne pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella typhimurium) with an inhibition zone of 4.5–22 mm. Moreover, the α‐diphenyl‐β‐picrylhydrazyl (DPPH) scavenging activity of NFs samples was located at the range of 20%–48%. These findings represent the Efficiency of the G‐loaded NLPs for use as bioactive compound in the zein‐based NFs as an active packaging material. [ABSTRACT FROM AUTHOR]

In the face of mounting environmental concerns, the textile industry is undergoing a pivotal transformation, with sustainability at the forefront of innovation. This review focuses on the exploration of natural compounds, renowned for their antimicrobial properties, as viable alternatives to conventional chemical agents that pose significant environmental challenges. It delves into a diverse array of natural sources, including plant extracts, essential oils, and microbial‐derived compounds, which have been identified for their potent antimicrobial efficacy. These natural agents not only demonstrate a broad spectrum of activity against pathogenic microorganisms but also represent a stride towards eco‐friendly textile processing by offering a sustainable substitute for synthetic antimicrobials. The integration of these green antimicrobial agents into textiles is scrutinized, with a particular emphasis on their impact on enhancing fabric functionalities. This includes improvements in durability, wash resistance, and the sustained antimicrobial effectiveness of treated fabrics, without sacrificing environmental integrity. Moreover, the study underscores the potential health benefits of these natural agents, such as a decrease in allergic reactions and skin irritations commonly associated with traditional antimicrobial treatments. The review culminates by highlighting the significant role these eco‐conscious solutions play in revolutionizing antimicrobial textiles, promoting industry‐wide sustainable practices, and catering to the escalating consumer demand for environmentally responsible products. Highlights: Provides eco‐friendly and sustainable alternatives in textile processing, offering a greener choice over synthetic options.Enhances fabric functionality while preserving environmental integrity, addressing sustainability concerns throughout production.Improves fabric durability, wash resistance, and long‐lasting efficacy, thereby contributing to superior product performance.Reduces allergic reactions and skin irritations, underscoring the health benefits of eco‐friendly antimicrobial treatments.Promotes sustainable practices, shaping the future of antimicrobial textiles and catering to the growing demand for environmentally conscious consumer choices in the industry. [ABSTRACT FROM AUTHOR]

Antimicrobial poly(vinyl alcohol) nanofibres are produced using AquaQure biocide as additive to the polymer solution. AquaQure is an aqueous antimicrobial agent containing mainly Cu2+ and Zn2+. Antimicrobial tests show that the fibres achieve up to a 5 log reductions in populations of E. coli, S. aureus, S. typhimurium, P. aeruginosa and K. pneumoniae bacteria. Reusability of the nanofibre membranes is investigated to establish if the nanofibres retain their morphology and antimicrobial effectiveness over six cycles of water filtration. Leaching of AquaQure constituents from the nanofibres into filtered water is assessed and found to be at acceptable levels. [ABSTRACT FROM AUTHOR]

Fatty acid esters of glycosides and glucopyranosiduronides were regioselectively synthesized with tin-mediated method using dibutyltin dimethoxide as the stannylating agent, these novel esters were investigated for their antibacterial activities against bacterial Staphylococcus Aureus and Salmonella Agona, the essential structural feature as antibacterial agents was probed. Antimicrobial tests showed that some laurates of trans-ol glycosides are effective inhibitors against S. Aureus, while some laurates and myristates of cis-ol glycosides are moderate inhibitors against both S. Aureus and S. Agona. Studies on antimicrobial structure-activity relationship of sugar fatty acid esters showed that both the carbohydrate moiety and the length of fatty acid played a vital role on the antibacterial effect. [ABSTRACT FROM AUTHOR]

The present study was aimed to investigate the polyphenolic profile of a pepper ( Capsicum annuum L.) extract from Algeria and evaluate its biological activity. The total polyphenol content of the extract was determined as 1.373 mg of gallic acid equivalents (±0.0046), whereas the flavonoids were determined as 0.098 mg of quercetin (±0.0015). The determination of the complete polyphenolic profile of the extract was achieved by liquid chromatography with an RP-amide column in combination with photodiode array and mass spectrometry detection through an electrospray ionization interface. A total of 18 compounds were identified, of which five were reported for the first time in the sample tested. Quercetin rhamnoside was the most abundant compound (82.6 μg/g of fresh pepper) followed by quercetin glucoside (19.86 μg/g). The antioxidant activity and antimicrobial effects were also determined. For the antimicrobial tests assessed against Gram-positive and Gram-negative bacteria, kaempferol showed the strongest inhibitory effect followed by quercetin and caffeic acids. In the study of the cytotoxicity of the extract, the cancer cells (U937) were more affected than the normal cells (peripheral blood mononucleated cells), with more than 62% inhibition at the highest concentration. [ABSTRACT FROM AUTHOR]

The aim of this research was synthesizing of bacterial cellulose (BC) nanohybrids by incorporation of CuO‐NPs and evaluation of their ability in the removing of microbial, heavy metals, and dyes pollutants from water. CuO‐BC nanohybrids were synthesized by two in situ (sonochemical and precipitation) methods and compared with ex situ synthesized nanohybrid. FE‐SEM images revealed that the growth of CuO‐NPs in the sonochemically synthesized in situ substrate is better. The ex situ nanohybrid had the highest loading capacity (27.17 μg/cm2) but the migration of CuO‐NPs from this substrate was higher than in situ ones. According to antimicrobial tests, 80% and 90% of initial population of E. coli and S. aureus, respectively, were removed after 6 hr contact of substrates with water. The potential of the substrates in the adsorption of lead and arsenic was about 60% after 24 hr. About 75% of methylene blue and methyl orange dyes were adsorbed into substrates after 6 hr. CuO doped substrates had the photocatalytic activity and caused to decrease the oxygen content about 4%–7% during 6 hr. In general, the reusability of ex situ synthesized substrate was lower than in situ nanohybrids. Sonochemically synthesized substrate was suggested as the best nanohybrid for water purification applications in terms of morphological properties and reusability. Practitioner points: CuO‐BC nanohybrids were prepared by in‐situ and ex‐situ methods.Well distribution of NPs and slower release was achieved by in‐situ methods.Antimicrobial and photocatalytic activity of ex‐situ nanohybrid was higher than in‐situ ones.Dyes and heavy metals were removed successfully with nanohybrid substrates.Sonochemical in‐situ nanohybrid exhibited the best water purification performance. [ABSTRACT FROM AUTHOR]

To investigate the effectiveness of antimicrobial agents against wound infections, experiments using either 2D cultures with planktonic microorganisms or animal infection models are frequently carried out. However, the transferability of the results to human skin is limited by the lack of complexity of the 2D models or by the poor translation of the results from animal models. Hence, there is a need for wound infection models capable of assessing antimicrobial agents. In this study, an easily standardized wound infection model was established. This model consists of a mechanically wounded human skin model on a collagen matrix infected with various clinically relevant bacteria. Infection of the model led to recognition of the pathogens and induction of an inflammatory response. The untreated infection spread over time, causing significant tissue damage. By applying an antimicrobial‐releasing wound dressing, the bacterial load could be reduced and the success of the treatment could be further measured by a decrease in the inflammatory reaction. In conclusion, this wound infection model can be used to evaluate new antimicrobial therapeutics as well as to study host‐pathogen interactions. [ABSTRACT FROM AUTHOR]

During the COVID‐19 pandemic, the use of polypropylene fleece‐based personal protection equipment (PPE) increased significantly to over ten million tons. Typically, most PPEs are discarded after a single use, to prevent self‐infection of users and spread of infectious agents. However, in order to minimize plastic waste without compromising the protective properties of PPE, it is crucial to explore new reusable or longer‐lived materials. Here, a visible light‐activatable antimicrobial photodynamic dye coating for PPEs is presented. In this context, coating with thiomorpholino‐methylene blue (TMB), derived from methylene blue by introducing two thiomorpholine units, is found to show high antibacterial activity. TMB is integrated into rotary printing suspension, a commercial nitrocellulose‐based printing matrix. The concentration of TMB in adhesive is optimized, and found that 5% TMB is suitable for coating PPE, for reducing the number of Gram‐positive and ‐negative bacteria by 99.99% after 6 h of white light irradiation. Bacterial filtration efficiency and breathability tested according to EN 14683, confirmed that TMB coating does not affect the filter performance. Thus, this antimicrobial photodynamic dye coating technique offers a promising solution for a safer and extended use of PPE, and reduction of plastic waste generated by PPEs. [ABSTRACT FROM AUTHOR]

In the setting of healthcare, the use of hand sanitizers and antiseptics for hand hygiene is of paramount importance to avoid transfer of pathogenic microorganism through hand and skin contact. There is an increasing interest in the incorporation of essential oils in hand sanitizer's formula to avoid the adverse effect of conventional hand sanitizers on health. This study aimed to detect the chemical constituents of citrus peel essential oils and study their antimicrobial activity compared with commercial hand sanitizers. The qualitative and quantitative analysis of the hydrodistillated essential oils of peels of grapefruit (Citrus paradisi), lime (Citrus aurantifolia), and orange (Citrus sinensis) were carried out using gas chromatography mass spectroscopy. The disc diffusion method was used to screen the antibacterial activity of the essential oils against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, and Candida albicans compared with a 78% alcohol-based commercial hand sanitizer. The antimicrobial testing results were statistically analyzed. The highest yield percentage of the obtained essential oils was 1.09% obtained by orange oil. The GC-MS analysis indicated that monoterpene and sesquiterpene hydrocarbons occupied the largest portion of the chemical composition of the three essential oils with D-limonene as the most predominant component. All essential oils showed activity against all tested organisms. Lime essential oil showed comparable antimicrobial activity relative to the commercial 78% alcohol hand sanitizer. In conclusion, essential oils obtained from citrus fruit peel represent a rich source of compounds possessing antimicrobial properties and could be an alternative to synthetic antimicrobial agents. [ABSTRACT FROM AUTHOR]

In this study, a good combination consisting of electrospun silk fibroin nanofibers incorporated with high-purity hydroxyapatite (HAp) nanoparticles (NPs) and silver NPs is introduced as antimicrobial for tissue engineering applications. The variable pressure field emission scanning electron microscope results confirmed randomly placed nanofibers are produced with highly dispersed HAp and silver NPs in nanofibers after electrospinning. The X-ray diffraction results demonstrated crystalline features of each of the three components used for electrospinning. Moreover, the TEM-EDS analysis confirmed the presence and chemical nature of each component over individual silk nanofiber. The FT-IR analyses was used confirm the different vibration modes caused due to functional groups present in silk fibroin, Hap, and silver NPs. The obtained nanofibers were checked for antimicrobial activity by using two model organisms Escherichia coli and Staphylococcus aureus. Subsequently, the antimicrobial tests have indicated that prepared nanofibers do possess good bactericidal activity. The ability of N,N-dimethylformamide and silk fibroin used to reduce silver nitrate into silver metal was evaluated using MTT assay. The nanofibers were grown in presence of NIH 3T3 fibroblasts, which revealed toxic behavior to fibroblasts at higher concentrations of silver nitrate used in this study. Furthermore, cell attachment studies on nanofibers for 3 and 12 days of incubation time were minutely observed and correlated with the results of MTT assay. The reported results confirmed the high amounts of silver nitrate can lead to toxic effects on viability of fibroblasts and had bad effect in cell attachment. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 3459-3469, 2014. [ABSTRACT FROM AUTHOR]

The genome of Vitis vinifera contains 79 defensin-like ( DEFL) gene sequences, classified in four groups based on peptide sequence similarity. Group-2 DEFL proteins are highly conserved peptides with 10 cysteine residues, and include VvAMP2, a defensin active against the fungal pathogen Botrytis cinerea. Here, quantitative reverse transcription- PCR (q RT- PCR) analysis was used to show that group-2 DEFLs are specifically expressed in grapevine inflorescences, with the highest level in pollen/stamen, and weak expression in calyptrae and carpels. Immunofluorescence microscopy showed that the protein accumulates in pollen grains and in specific areas of the ovary parenchyma, suggesting a role in grapevine fertilization. Antimicrobial tests showed that VvAMP2 inhibits the growth of B. cinerea, but not of other fungal pathogens, nor bacteria. Fluorescence microscopy analysis of B. cinerea cells treated with VvAMP2 revealed that this defensin is first internalized and then leads to membrane permeabilization, suggesting that membrane damage is a secondary effect of this plant defensin. To identify possible intracellular targets of VvAMP2, its inhibitory action was tested on 54 B. cinerea mutants, with deletions in key signalling genes. The ΔBcATF1 transcription factor mutant, impaired in regulation of cell wall and oxidative stress genes, completely lost sensitivity to VvAMP2. Mutants lacking the Rho-type GTPase BcCDC42, the G protein-coupled receptor BcGPR3 and the putative scaffold protein BcBEM1, showed very low sensitivity. [ABSTRACT FROM AUTHOR]

Silver nanoparticles are gaining importance as an antimicrobial agent in wound dressings. Chitin is a biopolymer envisioned to promote rapid dermal regeneration and accelerate wound healing. This study was focused on the evaluation of chitin membranes containing silver nanoparticles for use as an antimicrobial wound dressing. Silver nanoparticles were synthesised by gamma irradiation at doses of 50 kGy in the presence of sodium alginate as stabiliser. The UV-Vis absorption spectra of nanoparticles exhibited an absorption band at 415-420 nm, which is the typical plasmon resonance band of silver nanoparticles. The peaks in the X-ray diffraction (XRD) pattern are in agreement with the standard values of the face-centred cubic silver. Transmission electron microscopy (TEM) images indicate silver nanoparticles with spherical morphology and small particle size in the range of 3-13 nm. In vitro antimicrobial tests were performed using Pseudomonas aeruginosa and Staphylococcus aureus to determine the antimicrobial efficiency of the chitin membranes containing 30, 50, 70 and 100 ppm nanosilver. No viable counts for P. aeruginosa were detected with 70 ppm silver nanoparticles dressing after 1-hour exposure. A 2-log reduction in viable cell count was observed for S. aureus after 1 hour and a 4-log reduction after 6 hours with 100 ppm nanosilver chitin membranes. This study demonstrates the antimicrobial capability of chitin membranes containing silver nanoparticles. The chitin membranes with 100 ppm nanosilver showed promising antimicrobial activity against common wound pathogens. [ABSTRACT FROM AUTHOR]

A set of three analogs of the 10-residue, membrane-active lipopeptaibiotic trichogin GA IV, labeled with the promising 4-nitrophenylalanine IR absorption probe for local polarity, was synthesized by the solid-phase methodology, chromatographically purified, and extensively characterized. A single residue modification was inserted near the N-terminus, in the central region, or at the C-terminus. A solution conformational analysis, carried out by FT-IR absorption, CD, and 2D-NMR combined with molecular dynamics calculations, indicates that the mono-labeled analogs maintain the overall helical properties of the parent compound. Membrane permeabilization measurements and antimicrobial tests revealed that they possess membrane-modifying properties and in vitro antibacterial activities analogous to those of the natural lipopeptaibiotic. Our IR absorption and attenuated total reflectance investigations in various environments, from which water was excluded for solubility reasons, showed that the 1350 cm−1 4-nitrobenzyl band is a reporter group of rather limited sensitivity. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Antimicrobial textiles (65% cotton - 35% polyester) were functionalized using a patented technology that combines an antimicrobial molecule - polyhexamethylene biguanide (PHMB) and a precipitating agent - sodium laurylsulphate. Surface characterization was performed by x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, and both techniques made clear signatures of PHMB at the top surface of treated textiles. Washing led to a strong decrease of PHMB concentration at the surface. Comparison of textile surface analysis and antimicrobial tests indicated that the amount of PHMB at its extreme surface of textiles after five or 10 industrial washings was sufficient to inhibit Listeria innocua but not Pseudomonas aeruginosa growth. The viability of L. innocua cells after contact with PHMB-treated textile after one industrial washing was estimated using the Live/Dead BacLight kit (Molecular Probes, Eugene, OR): the combination of epifluorescence microscopy observations coupled with classic enumeration allowed detection of the presence of viable but nonculturable cells. PRACTICAL APPLICATIONS Protective clothing is required in the food-processing industry to protect products from being contaminated by microorganisms carried by workers' clothes or filtration systems. Consequently, there is an increasing interest in the use of antimicrobial functionalized textiles in the food industry to avoid that textiles could be vectors for pathogenic or food spoilage microorganisms. In the present study, the correlation between PHMB (the antimicrobial agent) at the surface of textiles (monitored by surface analysis characterization methods) and their antibacterial activity was assessed. After contact with antimicrobial textiles, the enumeration of bacteria was performed either by plate counting or by direct observation by epifluorescence microscopy in the presence of fluorescent viability markers in order to determine whether viable but nonculturable bacterial cells were present. [ABSTRACT FROM AUTHOR]

Surfaces of solid polymer foils were modified by chemical methods. Surfaces were firstly activated by Piranha solution and then grafted with selected amino‐compounds (cysteamine, ethylenediamine and chitosan). Next step was established of cobaltacarborane compound. Selected surface properties were studied using various available methods to characterize changes in surface chemistry (X‐ray photoelectron spectroscopy), charge and polarity (electrokinetic analysis), wettability (goniometry), surface roughness and morphology were studied by atomic force microscopy and scanning electron microscopy. Surface area with porosity by adsorption/desorption isotherms. The surface properties dramatically differ after individual activation and modification steps and can affect the adhesion properties. Also some antimicrobial tests were realized. Samples treated with cobaltcarborane compounds exhibit antimicrobial effects to algae D. quadricauda and to gram‐ positive bacteria S. epidermidis. It was confirmed this cobaltcarborane compound can be easily grafted on polymer surface by two ways (i) directly onto Piranha activated polymer surfaces and/or (ii) via amino‐ compounds previously grafted onto Piranha activated polymer surfaces. The most important fact is that its antimicrobial behaviour remains preserved also after its grafting onto polymer surface. These chemically modified polymers can be used in the fields of nanobiotechnology, tissue engineering studies, biomedicine or environment protection. [ABSTRACT FROM AUTHOR]

A reversed-phase high performance liquid chromatography (RP-HPLC) separation on C8 column and quantitative method were developed to analyse hydroxyl derivatives of benzoic and cinnamic acid and flavonoids in horsetail ( Equisetum arvense L.) extracts. Total phenolic content of n-butanol, ethyl acetate and water extracts, determined by the Folin-Ciocalteu method, was 96.4, 26.4 and 15.4 mg g−1 of dry extracts, respectively. The antioxidative activity of horsetail extracts was tested by measuring their ability to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reactive hydroxyl radicals by electron spin resonance spectroscopy. The results demonstrated that the free radical scavenging activity (versus both DPPH and hydroxyl radicals) depended on the type and concentration of applied extracts; the highest DPPH (EC50 = 0.65 mg mL−1) and hydroxyl radical scavenging activities (EC50 = 0.74 mg mL−1) were obtained in the case of n-butanol extract. The radical scavenging activity of extracts significantly correlated with total phenolic content. The antimicrobial tests showed that ethyl acetate and n-butanol extracts inhibited the growth of tested bacteria. [ABSTRACT FROM AUTHOR]

This paper presents a comparison of the chemical composition and biological activity of the volatile fraction (essential oil solution) of rhizomes of two plant species, Silphium trifoliatum L. and Silphium integrifolium Michx., and the respective soft ethanol and chloroform extracts; 51 components were identified in the extracts and oils (the main constituents of the oils were modhephene, α-isocomene, allo-aromadendr-9-ene, 7 α-H-silphiperfol-5-ene, 7 β-H-silphiperfol-5-ene and germacrene D). The studied initial essential oil solutions contained 336 mg/ml ( S. trifoliatum) and 406 mg/ml ( S. integrifolium) of volatile substances. The soft extracts contained between 15.84 mg/ml (ethanol extract, S. trifoliatum) and 35.65 mg/ml (ethanol extract, S. integrifolium) of substances identified with GC-MS. Additionally, the analysed soft extracts contained flavonoids, o-dihydroxyphenoles and glycoside-bonded triterpenic acids (oleanolic and ursolic acid). Antimicrobial tests were performed on two bacterial reference strains ( Staphylococcus aureus and Escherichia coli) and two fungal reference strains ( Candida albicans and Malassezia pachydermatis). The highest level of activity was displayed by essential oils, i.e. fractions rich in volatile components. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]