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Rapid distinguishing and detection of Gram-positive and Gram-negative bacteria with high sensitivity is essential for human health worldwide. Herein, an excellent fluorescence biosensing platform for bacterial identification and detection is constructed on the basis of boronic acid functionalized carbon dots (B-CDs). The B-CDs fluorescence probes were tightly attached to the bacterial surface through the interaction of the boronic acid group with glycolipids on the outside of bacterial cells. Our experimental results showed that the B-CDs displayed a stronger binding ability toward Gram-positive bacteria, enabling the specific detection of Gram-positive bacteria. More importantly, Gram-positive bacteria and Gram-negative bacteria differ in terms of their saccharide units on the cell wall, resulting in distinct fluorescence signals, which could be employed for distinguishing Gram-positive and Gram-negative bacteria. Taking S. aureus as a representative of Gram-positive bacteria, the results showed that the linear range of detection was 2.6 × 101–5.2 × 106 CFU mL−1 and the detection limit was 7 CFU mL−1. Our research provides great potential for further development of a novel platform for bacterial determination and identification. [ABSTRACT FROM AUTHOR]

Background: Different organic and inorganic bedding materials can be used in dairy farms. Among organic materials, there is an increasing interest in alternative substrates based on recycled manure solids (RMS). Microbiological analyses are crucial to monitor the microbial load and evaluate the presence of pathogens impacting animal welfare and health. However, logistic factors may hamper the possibility of immediately sending fresh samples to the laboratory, requiring storage in cooled conditions before analysis. Methods: We assessed the impact of sample refrigeration and freezing of different organic and inorganic bedding substrates including separated raw manure solids (SRMS), anaerobically digested manure solids (ADMS), and new sand (NS), on the total bacterial count (TBC) and on different microbial classes. Results: The TBC was higher in fresh NS and ADMS than in refrigerated and frozen samples of the same substrates; in addition, the TBC of ADMS was higher in refrigerated than frozen samples. The TBC of SRMS did not change significantly with refrigeration and freezing. Freezing reduced the total Gram-negative bacterial count more than refrigeration in all substrates. In fresh NS, Gram-negatives were higher than in both refrigerated and frozen NS. Escherichia coli counts were significantly lower in frozen than in refrigerated SRMS. However, both refrigeration and freezing of ADMS resulted in no E. coli growth. The coliform counts were also lower in frozen than refrigerated NS and SRMS. Frozen NS and ADMS showed lower counts compared to refrigeration for Gram-negative bacteria other than E. coli and coliforms. On the other hand, cold storage did not significantly impact the streptococci and streptococcus-like organisms (SSLO) count of all evaluated bedding substrates. Conclusion: Refrigeration and freezing affect the bacteriological results of bedding substrates, with freezing generally leading to lower counts than refrigeration. Whenever possible, preference should be given to analyzing fresh bedding samples, however, when necessary, refrigeration would be recommended over freezing, while acknowledging that the measured bacterial load might underestimate the actual microbial content. [ABSTRACT FROM AUTHOR]

Colistin is one of the last-resort antibiotics in treating infections caused by multidrug-resistant (MDR) pathogens. Unfortunately, the emergence of colistin-resistant gram-negative strains limit its clinical application. Here, we identify an FDA-approved drug, valnemulin (Val), exhibit a synergistic effect with colistin in eradicating both colistin-resistant and colistin-susceptible gram-negative pathogens both in vitro and in the mouse infection model. Furthermore, Val acts synergistically with colistin in eliminating intracellular bacteria in vitro. Functional studies and transcriptional analysis confirm that the combinational use of Val and colistin could cause membrane permeabilization, proton motive force dissipation, reduction in intracellular ATP level, and suppression in bacterial motility, which result in bacterial membrane disruption and finally cell death. Our findings reveal the potential of Val as a colistin adjuvant to combat MDR bacterial pathogens and treat recalcitrant infections. A colistin adjuvant valnemulin is identified to circumvent MDR bacterial pathogens and treat recalcitrant infections by causing membrane permeabilization, proton motive force dissipation, and reduction in intracellular ATP level. [ABSTRACT FROM AUTHOR]

The contagious respiratory pathogen, Avibacterium paragallinarum, contributes to infectious coryza in poultry. However, commercial vaccines have not shown perfect protection against infectious coryza. To search for an alternative approach, this research aimed to investigate whether the quorum-sensing system of pathogens plays a crucial role in their survival and pathogenicity. The LuxS/AI-2 quorum-sensing system in many Gram-negative and Gram-positive bacteria senses environmental changes to regulate physiological traits and virulent properties, and the role of the luxS gene in Av. paragallinarum remains unclear. To investigate the effect of the luxS gene in the quorum-sensing system of Av. paragallinarum, we constructed a luxS mutant. Bioluminescence analysis indicated that the luxS gene plays a vital role in the LuxS/AI-2 quorum-sensing system. The analysis of the LuxS/AI-2 system-related genes showed the level of pfs mRNA to be significantly increased in the mutant strain; however, lsrR, lsrK, and lsrB mRNA levels were not significantly different compared with the wild type. The ability of the luxS mutant strain to invade HD11 and DF-1 cells was significantly decreased compared with the wild-type strain. In addition, all chickens challenged with various doses of the luxS mutant strain developed infections and symptoms, and those challenged with the lowest dose exhibited only minor differences compared to chickens challenged with the wild-type strain. Thus, the deletion of the luxS gene reduces the invasion, but the luxS gene does not play an essential role in the pathogenesis of A. paragallinarum. [ABSTRACT FROM AUTHOR]

AbstractAsymmetric gemini surfactants were synthesized by the quaternization reaction of 1-(2-hydroxypropyl)-4-ethyl piperazine with (C9, C10, C12, and C14) alkyl bromides. The surface tension of their aqueous solutions was determined by the Du Nouy ring method and the conductometric method of specific electrical conductivity. According to the concentration dependence graphs of surface tension and specific electrical conductivity, critical micelle concentration – CMC, degree of association of the counterion – β, surface area occupied by the head group of the surfactant – Amin, maximum surface excess concentration – Γmax, effectiveness or surface pressure –πCMC, adsorption efficiency – pC20 were calculated, and the change of these parameters depending on the length of the alkyl chain was determined. Simultaneously, variations in Gibbs free energies of micellization and adsorption processes were computed. The diameters of aggregates formed by asymmetric gemini surfactants in water were determined by the DLS method. Antimicrobial abilities of asymmetric gemini surfactants against gram positive and gram negative bacteria and fungi were defined by the disk diffusion method. [ABSTRACT FROM AUTHOR]

The novel structure of Hg(II) complexes including the pyridinium ylide C5H5NCHC(O)C6H4-m-Br (Y) were synthesized and reported in this study. In the first step, the pyridinium salt C5H5NCH2C(O)C6H4-m-Br (S) was produced by reacting 2,3′-dibromoactophenone and pyridine. then, treatment of S with K2CO3 gave the related pyridinium ylide Y. Finally, the reaction of Y with HgX2 and Hg(NO3)2·H2O leads to the formation of novel binuclear [HgY2][HgX4] (X=Cl (1); X=Br (2); X=I (3)) and polymeric [HgY(NO3)2]n (4) complexes. The structure of complex 2 was also determined by X-ray diffraction analysis. The obtained analyses proved the coordination through the ylidic carbon to metallic center. Additionally, Natural Bond Orbital (NBO), Energy Decomposition Analysis (EDA), and EDA-NOCV studies are also used to investigate the nature of metal–ligand bonding in the complexes. Finally, the antibacterial activity of 1–4 was also examined against Gram positive and negative represented significant levels of inhibitory potency respected to used standards. [ABSTRACT FROM AUTHOR]

The emission of glyphosate and antibiotic residues from human activities threatens the diversity and functioning of the microbial community. This study examines the impact of a glyphosate-based herbicide (GBH) and common antibiotics on Gram-negative bacteria within the ESKAPEE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli). Ten strains, including type and multidrug-resistant strains for each species were analysed and eight antibiotics (cefotaxime, meropenem, aztreonam, ciprofloxacin, gentamicin, tigecycline, sulfamethoxazole-trimethoprim, and colistin) were combined with the GBH. While most combinations yielded additive or indifferent effects in 70 associations, antagonistic effects were observed with ciprofloxacin and gentamicin in five strains. GBH notably decreased the minimum inhibitory concentration of colistin in eight strains and displayed synergistic activity with meropenem against metallo-β-lactamase (MBL)-producing strains. Investigation into the effect of GBH properties on outer membrane permeability involved exposing strains to a combination of this GBH and vancomycin. Results indicated that GBH rendered strains sensitive to vancomycin, which is typically ineffective against Gram-negative bacteria. Furthermore, we examined the impact of GBH in combination with three carbapenem agents on 14 strains exhibiting varying carbapenem-resistance mechanisms to assess its effect on carbapenemase activity. The GBH efficiently inhibited MBL activity, demonstrating similar effects to EDTA (ethylenediaminetetraacetic acid). Chelating effect of GBH may have multifaceted impacts on bacterial cells, potentially by increasing outer membrane permeability and inactivating metalloenzyme activity. [ABSTRACT FROM AUTHOR]

1. Poultry farming faces challenges regarding correct hygiene and nutrition. One of the challenges is gram-negative bacteria that stimulate pro-inflammatory reactions through lipopolysaccharide (LPS) and cause disease and anorexia. Liquorice, a medicinal plant containing glycyrrhizin (Glz; a saponin and emulsifier compound) as its main active ingredient, was injected into broilers to investigate any beneficial effects on feed intake in LPS-injected broilers.2. The study involved three experiments using 72 male broiler chickens in each, to examine the impact of Glz on feed intake, especially when challenged with lipopolysaccharide (LPS) by intra-peritoneal (IP) injection to cause inflammation (n = 24). Experiment 1 was conducted to examine the effects of intraperitoneal injection of Glz (12.5, 25 and 50 mg) on feed intake in chickens. In experiment 2, the effects of intracerebroventricular injections of LPS (6.25, 12.5 and 25 ng) were examined. The third experiment investigated the impact of IP injection of Glz on inflammation induced by LPS.3. Injection of Glz significantly increased feed intake in a dose-dependent manner. Whereas LPS significantly reduced the feed intake in feed-deprived chickens (p < 0.05).4. In conclusion, Glz can neutralise the feed intake reduction caused by inflammation in broilers, highlighting its potential role in modulating feed intake in broilers. [ABSTRACT FROM AUTHOR]

Strategies facilitating the synthesis of heterocycles using green methodologies have modernized their syntheses in synthetic and pharmaceutical chemistry. In the present study, a highly well-organized, ecofriendly and straightforward synthetic approach was developed for the microwave-assisted synthesis of fused pyrazolopyridines and spirooxindole-fused pyrazolopyridines using an economical metal--organic framework, HKUST-1, in ethanol. The prepared MOF was characterized through diverse techniques, including FT-IR, p-XRD, SEM, TEM, EDX, TGA and BET. This approach shows noteworthy advantages, such as good yields, simple and clean reaction conditions, shorter reaction time, use of a highly efficient and sustainable catalyst and no chromatographic separation as the entire products can be purified through recrystallization. Moreover, green chemistry metrics for compounds 4a, 6a, 8a and 9a were calculated and were found to be very close to ideal values. The TON and TOF of the catalyst reached 32.75 and 3.27 min-1, respectively, for this transformation. In vitro anti-bacterial screening of these synthesized derivatives was performed against the Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive bacteria Staphylococcus aureus (S. aureus). Compounds 4a and 6f showed activity against all the bacteria tested in the experiment. Further, the anti-tubercular study of the synthesized compounds revealed that compound 4b had the highest activity among all the synthesized derivatives. [ABSTRACT FROM AUTHOR]

Carbapenem-resistant Klebsiella pneumoniae (CRKP) causes Gram-negative lung infections and fatal pneumonic sepsis for which limited therapeutic options are available. The lungs are densely innervated by nociceptor sensory neurons that mediate breathing, cough, and bronchoconstriction. The role of nociceptors in defense against Gram-negative lung pathogens is unknown. Here, we found that lung-innervating nociceptors promote CRKP pneumonia and pneumonic sepsis. Ablation of nociceptors in mice increased lung CRKP clearance, suppressed trans-alveolar dissemination of CRKP, and protected mice from hypothermia and death. Furthermore, ablation of nociceptors enhanced the recruitment of neutrophils and Ly6Chi monocytes and cytokine induction. Depletion of Ly6Chi monocytes, but not of neutrophils, abrogated lung and extrapulmonary CRKP clearance in ablated mice, suggesting that Ly6Chi monocytes are a critical cellular population to regulate pneumonic sepsis. Further, neuropeptide calcitonin gene-related peptide suppressed the induction of reactive oxygen species in Ly6Chi monocytes and their CRKP-killing abilities. Targeting nociceptor signaling could be a therapeutic approach for treating multidrug-resistant Gram-negative infection and pneumonic sepsis. [ABSTRACT FROM AUTHOR]

Background: Bacterial pneumonia is among the leading causes of morbidity and mortality worldwide. The extensive misuse and overuse of antibiotics observed during the Corona Virus Disease 2019 (COVID-19) pandemic may have changed the patterns of pathogens causing bacterial pneumonia and their antibiotic susceptibility profiles. This study was designed to establish the prevalence of culture-confirmed bacterial pneumonia and describe their antimicrobial susceptibility profile in adult patients who presented with signs and symptoms of lower respiratory tract infections (LRTIs) during the COVID-19 pandemic. Methodology: This hospital-based cross-sectional study was conducted from July 2021 to July 2022 at a zonal referral hospital and two district hospitals in Mwanza, Tanzania. Demographic and clinical data were collected using a standardized questionnaire. Sputum samples were processed by conventional culture followed by the identification of isolates and antibiotic susceptibility testing. Descriptive data analysis was performed using STATA version 15.0. Results: A total of 286 patients with a median age of 40 (IQR 29–60) years were enrolled in the study. More than half of the patients enrolled were females (52.4%, n = 150). The overall prevalence of bacterial pneumonia was 34.3% (n = 98). The majority of the bacterial pathogens isolated were Gram-negative bacteria (GNB) (61.2%, 60/98), with a predominance of Klebsiella spp., 38.8% (38/98), followed by Streptococcus pyogenes (21.4%, 21/98). Multi drug resistant (MDR) bacteria were detected in 72/98 (73.5%) of the isolates. The proportions of GNB-resistant strains were 60.0% (36/60) for ciprofloxacin, 60% (36/60) for amoxicillin, 60% (36/60) for amoxicillin, 68.3% (41/60) for trimethoprim-sulfamethoxazole and 58.3% (35/60) for ceftriaxone. Conclusion: One-third of the patients with signs and symptoms of LRTIs had laboratory-confirmed bacterial pneumonia with a predominance of Gram negative MDR bacteria. This calls for continuous antimicrobial resistance (AMR) surveillance and antimicrobial stewardship programs in the study setting and other settings in developing countries as important strategies for tackling AMR. [ABSTRACT FROM AUTHOR]

Introduction Bloodstream infections are a significant threat to soldiers wounded in combat and contribute to preventable deaths. Novel and combination therapies that can be delivered on the battlefield or in lower roles of care are urgently needed to address the threat of bloodstream infection among military personnel. In this manuscript, we tested the antibacterial capability of silver ions (Ag+), with long-appreciated antibacterial properties, against ESKAPEE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species, and Escherichia coli) pathogens. Materials and Methods We used the GENESYS (RAIN LLC) device to deliver Ag+ to Gram-positive and Gram-negative ESKAPEE organisms grown in broth, human blood, and serum. Following the Ag+ treatment, we quantified the antibacterial effects by quantifying colony-forming units. Results We found that Ag+ was bactericidal against 5 Gram-negative organisms, K pneumoniae, A baumannii, P aeruginosa , E cloacae , and E coli , and bacteriostatic against 2 Gram-positive organisms, E faecium and S aureus. The whole blood and serum inhibited the bactericidal activity of Ag+ against a common agent of bloodstream infection, P aeruginosa. Finally, when Ag+ was added in conjunction with antibiotic in the presence of whole blood, there was no significant effect of Ag+ over antibiotic alone. Conclusions Our results confirmed that Ag+ has broad-spectrum antibacterial properties. However, the therapeutic value of Ag+ may not extend to the treatment of bloodstream infections because of the inhibition of Ag+ activity in blood and serum. [ABSTRACT FROM AUTHOR]

The arsRBC operon encodes a three-protein arsenic resistance system. ArsR regulates the transcription of the operon, while ArsB and ArsC are involved in exporting trivalent arsenic and reducing pentavalent arsenic, respectively. Previous research into Agrobacterium tumefaciens 5A has demonstrated that ArsR has regulatory control over a wide range of metal-related proteins and metabolic pathways. We hypothesized that ArsR has broad regulatory control in other Gram-negative bacteria and set out to test this. Here, we use differential proteomics to investigate changes caused by the presence of the arsR gene in human microbiome-relevant Escherichia coli during arsenite (AsIII) exposure. We show that ArsR has broad-ranging impacts such as the expression of TCA cycle enzymes during AsIII stress. Additionally, we found that the Isc [Fe-S] cluster and molybdenum cofactor assembly proteins are upregulated regardless of the presence of ArsR under these same conditions. An important finding from this differential proteomics analysis was the identification of response mechanisms that were strain-, ArsR-, and arsenic-specific, providing new clarity to this complex regulon. Given the widespread occurrence of the arsRBC operon, these findings should have broad applicability across microbial genera, including sensitive environments such as the human gastrointestinal tract. [ABSTRACT FROM AUTHOR]

We developed a synthesis strategy involving a diazo transfer reaction and subsequent click reaction to conjugate a murine cathelicidin-related antimicrobial peptide (CRAMP18–35) to chitosan and hydroxypropyl chitosan (HPC), confirmed the structure, and investigated the antimicrobial activity. Chitosan azide and HPC-azide were prepared with a low degree of azidation by reacting the parent chitosan and HPC with imidazole sulfonyl azide hydrochloride. CRAMP18–35 carrying an N-terminal pentynoyl group was successfully grafted onto chitosan and HPC via copper-catalyzed azide–alkyne cycloaddition (CuAAC) reaction. The chitosan–peptide conjugates were characterized by IR spectroscopy and proton NMR to confirm the conversion of the azide to 1,2,3-triazole and to determine the degree of substitution (DS). The DS of the chitosan and HPC CRAMP18–35 conjugates was 0.20 and 0.13, respectively. The antibacterial activity of chitosan–peptide conjugates was evaluated for activity against two species of Gram-positive bacteria, Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis), and two species of Gram-negative bacteria, Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). The antimicrobial peptide conjugates were selectively active against the Gram-negative bacteria and lacking activity against Gram-positive bacteria. [ABSTRACT FROM AUTHOR]

Outer membrane vesicles (OMVs) are nanostructures derived from the outer membrane of Gram-negative bacteria. We previously demonstrated that vaccination with endotoxin-free OMVs isolated from an Acinetobacter baumannii strain lacking lipooligosaccharide (LOS) biosynthesis, due to a mutation in lpxD, provides full protection in a murine sepsis model. The present study characterizes the protein content of highly-purified OMVs isolated from LOS-replete and LOS-deficient strains. Four purification methods were evaluated to obtain highly purified OMV preparations: ultracentrifugation, size exclusion chromatography (SEC), ultracentrifugation followed by SEC, and Optiprep™. OMVs from each method were characterized using nanoparticle tracking analysis and electron microscopy. OMVs from LOS-deficient and LOS-replete strains purified using the Optiprep™ method were subjected to LC-MS/MS analysis to determine protein content. Significant differences in protein composition between OMVs from LOS-deficient and LOS-replete strains were found. Computational analyses using Bepipred 3.0 and SEMA 2.0 indicated that the lack of LOS led to the overexpression of immunogenic proteins found in LOS-containing OMVs and the presence of immune-stimulating proteins absent in LOS-replete OMVs. These findings have important implications for developing OMV-based vaccines against A. baumannii, using both LOS-containing and LOS-free OMVs preparations. [ABSTRACT FROM AUTHOR]

The gut microbiota influences the effectiveness and side effects of cancer treatments, particularly immunotherapy and associated immune-related complications. This important involvement of the microbiome is supported by the patients receiving antibiotics responding poorly to immunotherapy. Relatively few research has examined the underlying processes, and until recently, data regarding the detection of the microbial organisms that trigger these effects were inconsistent. Since then, a deeper comprehension of the processes of action and taxonomic classification of the relevant species has been attained. It's been demonstrated that certain bacterial species can enhance the body's reaction to immune checkpoint inhibitors through the release of distinct metabolites or products. Nonetheless, in certain patients who are not responding, Gram-negative bacteria may have a dominating suppressive impact. Patients' propensity to react to immunotherapy can be somewhat accurately predicted by machine learning techniques based on their microbiome makeup. Consequently, there has been an increase in interest in modifying the microbiome makeup to enhance patient reaction to medication. Clinical proof-of-concept studies demonstrate that dietary modifications or fecal microbiota transplantation (FMT) might be used therapeutically to increase the efficacy of immunotherapy in cancer patients. Current developments and new approaches for microbiota-based cancer treatments have been emphasized. In conclusion, preclinical research on animals and human clinical trials has made tremendous progress in our understanding of the function of the gut microbiome in health and illness. These investigations have shed light on the effects of food, FMT, probiotics, prebiotics, and microbiome-disease connections. However, there are still a lot of issues and restrictions that must be resolved before this research can be used in real-world clinical settings. [ABSTRACT FROM AUTHOR]

Multidrug-resistant or extended drug resistance has created havoc when it comes to patient treatment, as options are limited because of the spread of pathogens that are extensively or multidrug-resistant (MDR or XDR) and the absence of novel antibiotics that are effective against these pathogens. Physicians have therefore started using more established antibiotics such as polymyxins, tetracyclines, and aminoglycosides. Fosfomycin has just come to light as a result of the emergence of resistance to these medications since it continues to be effective against MDR and XDR bacteria that are both gram-positive and gram-negative. Fosfomycin, a bactericidal analogue of phosphoenolpyruvate that was formerly utilised as an oral medication for uncomplicated urinary tract infections, has recently attracted the interest of clinicians around the world. It may generally be a suitable therapy option for patients with highly resistant pathogenic infections, according to the advanced resistance shown by gram-negative bacteria. This review article aims to comprehensively evaluate the impact of fosfomycin on gram negative infections, highlighting its mechanism of action, pharmacokinetics, clinical efficacy, and resistance patterns. [ABSTRACT FROM AUTHOR]

Bacterial resistance has led to the spread of bacterial infections such as chronic wound infections. Finding solutions for combating resistant bacteria in chronic wounds such as Staphylococcus aureus and Pseudomonas aeruginosa became an attractive theme among researchers. P. aeruginosa is a gram negative opportunistic human pathogenic bacterium that is difficult to treat due to its high resistance to antibiotics. S. aureus (gram negative bacterium) also has a high antibiotic resistance, so that it is resistant to vancomycin (VRSA), tetracycline, fluoroquinolones and beta-lactam antibiotics including penicillin and methicillin (MRSA). In particular, S. aureus and P. aeruginosa have intrinsic and acquired antibiotic resistance, making the clinical management of infection a real challenge, especially in patients with comorbidities. aPDT can be proposed as a new method in the treatment of multi-drug resistant bacteria in chronic wound infection conditions. In this study, the effect of saponin (100 μg/mL) on photodynamic inactivation on planktonic and biofilm forms of P. aeruginosa (ATCC 27853) and S. aureus (ATCC 25923) strains and on Human Dermal Fibroblast (HDF) cells was investigated. Methylene blue (MB) was used as photosensitizer (0, 10, 50, 100 μg/mL). The light source was a red LED source (660 nm; power density: 20 mW/cm2) which is related to the maximum absorption of MB. The results showed that the use of saponin in combination with MB-aPDT (Methylene Blue-antibacterial photodynamic therapy) reduces the phototoxic activity of MB due to decreasing the monomer form of MB. This result was obtained by spectrophotometric study. Also, the result of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay showed that 8 min of irradiation (660 nm) at 10 μg/mL concentration of alone MB had the lowest phototoxic effect on HDF cells. Due to reduced phototoxic properties of MB in this method, detergents containing saponins not recommended to applied at the same time with MB-aPDT in wound infection area. [ABSTRACT FROM AUTHOR]

A Gram-negative, short-rod, non-motile, facultatively anaerobic, potassium-solubilizing bacterium MR1 (Mine Rhizosphere) was isolated from rhizospheric soil of an open-cast coal mine of Jharia, Jharkhand, India. Isolate MR1 can grow in a broad range of temperature, pH, and NaCl concentrations. The 16S rRNA gene sequence of the strain showed 99.24% similarity with Pantoea septica LMG 5345T. However, maximum-likelihood tree constructed using 16S rRNA gene sequence, multilocus sequence analysis using concatenated sequences of ten housekeeping genes, whole-genome based phylogenetic reconstruction, digital DNA–DNA hybridization, and average nucleotide identity (ANIm and ANIb) values indicated segregation of MR1 from its closest relatives. Fatty acid profile of MR1 also suggested the same, with clear variation in major and minor fatty acid contents, having C13:0 anteiso (10-Methyldodecanoic acid) as the unique one. Thus, considering all polyphasic data, strain MR1T (= MTCC 13265T, where 'T' stands for Type strain) is presented as a novel species of the genus Pantoea, for which the name Pantoea tagorei sp. nov. is proposed. [ABSTRACT FROM AUTHOR]

The synthesis of Al-ZnO nanoparticles (NPs) was achieved using a green synthesis approach, utilizing leaf extract from Anisomeles indica (L.) in a straightforward co-precipitation method. The goal of this study was to investigate the production of Al-ZnO nanoparticles through the reduction and capping method utilizing Anisomeles indica (L.) leaf extract. The powder X-ray diffraction, UV spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy with EDAX analysis were used to analyze the nanoparticles. X-ray diffraction analysis confirmed the presence of spherical structures with an average grain size of 40 nm in diameter, while UV–visible spectroscopy revealed a prominent absorption peak at 360 nm. FTIR spectra demonstrated the presence of stretching vibrations associated with O-H, N-H, C=C, C-N, and C=O as well as C-Cl groups indicating their involvement in the reduction and stabilization of nanoparticles. SEM image revealed the presence of spongy, spherical, porous agglomerated nanoparticles, confirming the chemical composition of Al-ZnO nanoparticles through the use of the EDAX technique. Al-ZnO nanoparticles showed increased bactericidal activity against both Gram-positive and Gram-negative bacteria. The antioxidant property of the green synthesized Al-ZnO nanoparticles was confirmed by DPPH radical scavenging with an IC50 value of 23.52 indicating excellent antioxidant capability. Green synthesized Al-ZnO nanoparticles were shown in in vivo studies on HeLa cell lines to be effective for cancer treatment. Additionally, α-amylase inhibition assay and α-glucosidase inhibition assay demonstrated their potent anti-diabetic activities. Moving forward, the current methodology suggests that the presence of phenolic groups, flavonoids, and amines in Al-ZnO nanoparticles synthesized with Anisomeles indica (L.) extract exhibit significant promise for eliciting biological responses, including antioxidant and anti-diabetic effects, in the realms of biomedical and pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Background: Sepsis is a global healthcare issue and continues to cause high mortality especially in elderly patients. The present study was undertaken to study the clinical profile of sepsis in geriatric patients and to determine the predictors of mortality. Method: A total 201 patients of either sex, age >60 years with clinical and laboratory evidence of sepsis as per the International Sepsis definitions Conference criteriawere included in the study. Results: Out of 201 patients, 73.1% had comorbidity. 27.3% patients were found to be in septic shock on admission with mean arterial pressure ≤65mmHg according to sepsis 3 defining criteria.About 21% patients had culture negative sepsis. 39% patients had gram negative sepsis; 12% patients had gram positive sepsis.Pneumonia was the most common observed infection (33.8%), followed by urinary tract infection (24.4%), cellulitis (13.4%).56.7% patients required mechanical ventilation (MV) with survival of only 40.5%. Need for MV was found to be highly related to mortality (p<0.001). About 34.3% patients were provided with renal replacement therapy (RRT) and out of 69 only 34(16.92%) survived despite therapy, (p=0.004).Out of all the factors studied upon univariate analysis Age, SBP, Oxygen saturation, PaO2/FiO2 ratio, GCS score, haemoglobin, serum lactate levels, SOFAS score on day 1,3,5 were found to be significant predictors of mortality. On Multivariate regression analysis, significant predictors of mortality as an outcome were age, GCS score on admission, lower haemoglobin, increased Serum lactate and SOFAS score on Day 1 & 5.Conclusion: Present study described the clinical profile and mortality predictive factors in geriatricpatients with sepsis. These informative predictors would inform clinical practice to adopt effective therapeutic strategies to improve patient outcomes. [ABSTRACT FROM AUTHOR]

Introduction: A chronic inflammation of the middle ear and mastoid cavity that lasts more than two weeks is known as chronic suppurative otitis media (CSOM). A common organism that causes CSOM is pseudomonas aeruginosa. Although carbapenems are among the best medicines for treating Pseudomonas infections, the development of metallo-ß-lactamases strains is frequently linked to carbapenem resistance. Finding strains that produce MBLs can help ensure that patients receive the best care possible to stop the development of resistance. Finding the imipenem-resistant Pseudomonas aeruginosa carrying the metallo-ß-lactamase (MBL) geneblaIMP-1 is the primary goal of the research. Aim and Objective: To study the Molecular Characterization of Metallo-Beta Lactamase Gene blaIMP-1 in Imipenem Resistant Pseudomonas aeruginosa isolates from Patients of Chronic Suppurative Otitis Media. Material and Methods: This was a cross sectional study carried out in the Department of Microbiology and ENT Department for a period of 1 year i.e, May 2023 to May 2024. A total of 200 patients clinically suspected cases for CSOM was studied. Swabs taken from discharging ears were sent for Gram’s staining, culture and antibiotic sensitivity test as per the latest CLSI guidelines 2023. The DNA was extracted by using Qiagen DNA Extraction kit and blaIMP-1 gene for Pseudomonas aeruginosa isolates was detected by conventional PCR. Results: In the present study the number of cases clinically diagnosed of having CSOM were 200, out of which 70 (35%) was found to be culture positive for CSOM infection. Males were 44 (62.8%) as compared to that of female 26 (37.1%), the age group of 0-10 years followed by 11-20 years were being affected the most and the least number of cases was seen in the age group above 51 years. The side of the ear affected was almost in equal distribution, with the left ear being (51.4%) and the right ear being (40%) while (8.5%) were bilateral. In our study it was observed that the maximum number of cases was found in Gram negative isolates (98.5%) as compared to the Gram positive isolates (14.2%). It was also observed that 62 isolates (88.5%) samples showed growth of single isolates while 8 (11.4%) were mixed isolates. Pseudomonas aeruginosa being the most common isolate with 42.8% followed by Klebsiella sp. with 21.4% and among gram positive isolates Staphylococcus aureus was 11.4% and Streptococcus pneumonia (2.8%) being the least observed. The sensitivity observed in P. aeruginosa for Colistin was (97.1%), Piperacillin‑tazobactam (78.5%), Amikacin (82.8%), and cefepime (78.5%) were found to be the most effective Antibiotics. The resistance to ciprofloxacin was (56.6%), Levofloxacin (50%), Piperacillin(46.6%), Gentamicin(37.1%), Imipenem (31.4%), Tobramycin(31.4%), Ceftazidime (31.4%) and Gentamycin (37.1%). The blaIMP-1 gene was detected in 14 (20%) of the isolates of Pseudomonas aeruginosa Conclusion: Pseudomonas aeruginosa was the most frequently isolated strain in the current investigation, and the most effective antibiotics were cefepime, amikacin, piperacillin-tazobactam, and colonistin, ciprofloxacin and levofloxacin were the least effective. The Kanpur region (%) is seeing an increase in P. aeruginosa isolate resistance to imipenem as a result of MBL enzymes. Understanding the CSOM etiological agents and their antibiogram is crucial for effective treatment and prevention of antimicrobial resistance as well as clinical consequences. [ABSTRACT FROM AUTHOR]

Introduction: Infections associated with orthopaedic implants, especially prosthetic joint infections (PJIs) are increasing with advancement in joint arthroplasty. The reported prevalence of PJI out to 2 years after hip replacement is 1.63% and after knee replacement is 1.55%. PJI for the individual patient is devastating with increased rate of mortality, increased risk of morbidity, decreased quality of life, and potential for decreased level of mobility and ambulation. Rapid detection of infection is of paramount importance because delaying the start of treatment of PJI may result in the loss of the device. The consequence of PJI is quite severe at the patient as well as the healthcare system level. Hence this study was done to understand clinical profile, risk factors, and treatment outcome which can guide clinicians in appropriate management. Methodology: A retrospective study was done in cohort of patients in a tertiary care diagnosed as periprosthetic joint infections as per guidelines by infectious disease society of America. All the patients’ records holding diagnosis as PJIs during January 2021 to December 2023 were included. After obtaining permission from institutional ethical committee clearance, data from patient’s medical records were collected and analysed. Data on patients’ socio-demographic characteristics, clinical profile, investigations, treatment modalities and outcome were retrieved. A total of 50 such patients’ records were analysed. The data were analyzed using statistical package for the social sciences (SPSS) version 20. Chi square test and students t test was used with P<0.05 considered as statistically significant. Results: Commonest symptom was joint swelling in 100%, followed by pain in joint in 86%, erythema in 84% and fever in 40%. Other symptoms were outflow around the scar and fistula in 8% and 16% respectively. PJIs were early onset, delay onset and late onset in 64%, 24% and 12% respectively. Culturally positive PJIs were 80%. On culture microbes identified were staphylococcus aureus in 44%, pseudomonas in 16%, Gram negative organisms in 16% and Enterococci in 4%. Management done with debridement, antibiotics, implant retention (DAIR), 1 stage implant exchange, 2 stage implant exchange, arthrodesis and amputation in 78%, 8%, 4%, 4% and 6% patients respectively. Function was restored in 76% and death seen in 4% of patients respectively. Conclusion: Mean haemoglobin, mean serum albumin, mean serum calcium was found to be significantly less in patients with delayed or late onset PI when compared to early onset PJI. Leucocyte count of synovial fluid and mean CRP was significantly higher in patients with delayed or late onset PJI when compared to early onset PJI. [ABSTRACT FROM AUTHOR]

There is a focus on using aromatic phosphinous amide as an antibacterial agent against serious multidrug resistant bacterial infections. N-(4-acetylphenyl)-P,P-diphenyl-phosphinous amide and its corresponding thioxophosphinous amide and selenoxo-phosphinous amide were synthesized and designated Ph1, Ph2, and Ph3, respectively. They were structurally identified by single crystal X-ray diffraction, multinuclear NMR spectroscopy, and elemental analysis. Because their antibacterial activities have never been examined, this study aimed to assess their antibacterial activities against both Gram-positive and Gram-negative bacteria as well as readily available standard bacterial strains. Two bacterial isolates were isolated from urine specimens collected from patients with urinary tract infections and designated CS1, and CS2. Phenotypic, biochemical, and molecular approaches were used to identify them. The antibiotic susceptibility/resistance pattern of these isolates was examined by the installed VITEK 2 system. Isolate CS1 is an aerobic Gram-positive, straight rod-shaped, spore forming, occurring singly or in a short chain, whereas isolate CS2 is an aerobic Gram-negative, coccobacilli-shaped, non-spore forming, occurring in pairs or in chains. Both isolates are positive for catalase and oxidase test. According to an examination of the 16S rRNA gene sequence, the isolates CS1 and CS2 have 98% of their similarities with Bacillus and Acinetobacter species, respectively. Isolates CS1 and CS2 are multidrug resistance species. Based on the results of the minimum inhibitory concentration, the standard bacterial strains and isolates CS1 and CS2 showed a wide range in the antibacterial capabilities of the studied phosphinous amides. In comparison to Ph2 and Ph3, Ph1 has the strongest antibacterial activity against all of the tested bacterial species. In conclusion, CS1 and CS2 isolates were identified as novel, multi-drug resistant members of the Bacillus and Acinetobacter genera, respectively. The Ph1 molecule represents a promising new generation of antibiotics with notable antibacterial efficacy against multidrug-resistant Gram-positive and Gram-negative microorganisms. [ABSTRACT FROM AUTHOR]

This study was taken up to determine the prevalence of potential pathogens in most touched fomites in Neonatal Intensive Care Units (NICUs) and to determine their antibiogram. Fifty swabs each were collected from fomites from In-born (for babies born in our center) and out-born (for babies born elsewhere, brought to our center) NICUs, before and after cleaning. Samples were processed using standard Microbiological techniques. Antibiogram was determined by Kirby-Bauer disc diffusion method. From In-born NICU, before cleaning, 42 (84%) samples yielded growth with 48 bacterial isolates of which 31 (64.6%) were pathogens and after cleaning, 40 (80%) samples yielded growth with 41 bacterial isolates, of which 30 (73.1%) were pathogens. Most frequent isolates were non-fermenting gram-negative bacilli (NFGNB) and Klebsiella pneumoniae before and after cleaning, respectively. Prevalence of bacteria from In-born NICU before and after the cleaning was statistically significant (p = 0.025). From Out-born NICU, before cleaning, 42 (84%) samples yielded growth with 45 bacterial isolates, of which 25 (55.55%) were pathogens. Samples collected after cleaning; 42 (84%) samples yielded growth with 43 bacterial isolates of which 19 (44.18%) were pathogens. Most frequent isolates were NFGNB and Klebsiella pneumoniae from In-born NICU and K. pneumoniae and Escherichia coli from Out-born NICU before and after cleaning, respectively. Overall prevalence of pathogens was significant (p = 0.007). Staphylococcal isolates were resistant to Methicillin. NFGNB exhibited highest resistance (55.9%) towards Gentamicin. Significant decrease in the frequency of pathogens after cleaning indicates stringent practice of sterilization protocol would be essential in hospital environment. [ABSTRACT FROM AUTHOR]

The main goal of this research is to assess the antibacterial effectiveness of commonly used UAE natural herbs, including Turmeric, Henna, Sidr, and Myrrh, against a range of bacteria such as Staphylococcus aureus, Streptococcus agalactiae (group B streptococci), Streptococcus pyogenes (group A streptococci), Escherichia coli, Enterococcus faecalis, Proteus mirabilis, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Agar diffusion technique was utilized in this study. The herbs were extracted and prepared in serial dilution, a standardized amount of the test microorganisms were inoculated on the agar plates. Subsequently, extracted herbs were placed in the wells that formed on the surface of the media. The agar plates are then incubated at 37°C under appropriate condition. Typically, the herbs extract diffuses in the media, inhibiting the germination of the bacteria, the zone of inhibition is subsequently measured. Significant inhibitory effects were observed with henna herbal extract against 75% of Gram-positive bacteria, while 25% of the bacteria showed inhibition when using sidr extract. Myrrh exhibited an antibacterial effect against most tested bacteria. Comparatively less of an impact was seen by turmeric extract on both Gram-negative and Gram-positive. The antibacterial efficacy of the four plant extracts suggests that Henna displayed the highest effectiveness, followed by Sidr and Myrrh, with Turmeric showing the least potency. Additionally, strains such as E. coli, E. faecalis, P. aeruginosa, K. pneumoniae, and P. mirabilis demonstrated resistance to the plant extracts, while S. aureus, S. pyogenes, and S. agalactiae appeared to be the most susceptible strains. These findings underscore the potential of plant extracts in treating bacterial infections, offering insights for the development of novel compounds with enhanced activity against both resistant and susceptible bacteria, thereby addressing the limitations of current antibiotic agents. [ABSTRACT FROM AUTHOR]

This study aims to isolate and characterise the Pink Pigmented Facultative Methylotrophs (PPFM) bacteria from the leaves of common Malaysian table salad (ulam). The colonies of PPFM bacteria were obtained using selectively modified Pseudomonas agar based on the appearance of the pink pigment colony. The three selected isolates labelled OJ4, OJ154 [Oenanthe javanica (Blume) DC.] and ML8 [from Melicope lunu-ankenda (Gaertn.) T. G. Hartley] were chosen for characterisation. The result showed the PPFM bacteria colonies (log CFU/g) at the leaf surface of C. caudatus are 4.4 ± 0.1, significantly higher than O. javanica, 3.8 ± 0.2, and M. lunu-ankenda, 3.2 ± 0.1. The selected isolates belong to the Gram-negative group, motile with rod shape with size [length (l) × width (w)] in µm unit 4.3 ± 1.1 × 1.6 ± 0.6, 5.4 ± 0.2 × 1.2 ± 0.1, and 3.5 ± 0.7 × 1.0 ± 0.0, respectively. They show positive urease, catalase, and oxidase activities, while none of them can degrade starch, gelatine, or cellulose, as well as glucose fermentation (MR test) and metabolism actions (VP test), producing indole and hydrogen sulphide gaseous. Only isolate OJ154 demonstrates positive casein hydrolysis and nitrate reduction activities, while only isolate ML8 can utilise citrate but not in lipid degradation. Their sequence analysis of the 16S rRNA indicated that OJ4 and ML8 are Methylobacterium radiotolerans with a similarity of 99%, whereas, OJ154 is Methylorubrum salsuginis with a similarity of 99%. To conclude, PPFM bacteria from the leaves of C. caudatus, O. javanica, and M. lunu-ankenda have been isolated and characterised in particular. [ABSTRACT FROM AUTHOR]

Multidrug-resistant (MDR) Gram-negative bacterial infections have emerged as a major public health concern. The aim of the present study was to detect the rate of infections due to MDR Gram-negative bacteria (GNB) in a tertiary care hospital, the rate of Carbapenemases and AmpC-b-lactamases production and the Antimicrobial susceptibility test pattern (AST) among MDR GNB. The rate of MDR GNB during the study period was 25.70%. Urine samples showed the highest contribution to the total MDR GNB. Among the total MDR GNB isolates, 166 were randomly selected and included in the present study. A higher rate of MDR GNB was reported among male patients (61.5%) compared to the females (38.5%) and most of them were from the patients aged between 61-70 years (30.7%). The most prevalent MDR GNB was Klebsiella pneumoniae 80 (48.12%), followed by Escherichia coli 43 (25.9%). AST of MDR GNB revealed their significant resistance to b-lactamases/b-lactamases inhibitors, cephalosporins, fluoroquinolones and carbapenem drugs (98%). Of 123 MDR Enterobacterales, 83% of them were found to be Metallo b-lactamase (MBLs) producers by mCIM and eCIM methods. Of 43 MDR non-fermenters, 29 (67.4%) of them were found to be carbapenemase producers by MHT. About 29.51% of MDR GNB isolates were found to be AmpC producers by AmpC disk test. A reliable and rapid phenotypic method to detect carbapenemases and AmpC b-lactamases among MDR GNB in a routine microbiology laboratory method is clinically important to guide antibiotic therapy and implementation of effective infection control practices. [ABSTRACT FROM AUTHOR]

Emerging resistance of Gram-negative bacteria, including Pseudomonas aeruginosa, to commonly used detergents and disinfectant is encountering us with hazard. Inappropriate use of disinfectants has forced bacteria to gain resistance. The ability of bacteria to extrude substrates from the cellular interior to the external environment has enabled them to persist in exposure to toxic compounds, which is due to existence of transport proteins. Efflux pumps, in Gram-negative bacteria, are proteins responsible for exporting molecules outside of the cell, by crossing the two membranes. In this study, 40 P. aeruginosa strains from hospitals, clinics, and burn center laundries and 40 P. aeruginosa strains from urban laundries were collected. This study evaluated the minimum inhibitory concentration (MIC) level of sodium dodecyl sulfate (SDS), didecyldimethylammonium chloride (DDAC), and octenidine dihydrochloride (Od) in P. aeruginosa strains. The real-time PCR was carried out to evaluate the expression of MexAB-OprM, MexCD-OprJ, and MexXY-OprM efflux system. The obtained results indicated a higher MIC level for SDS, DDAC, and Od in medical laundries. The sub-MIC level of DDAC and Od increased the expression level of MexAB-OprM, MexCD-OprJ, and MexXY-OprM in P. aeruginosa strains, suggesting that efflux pumps contribute to disinfectant resistance in P. aeruginosa. [ABSTRACT FROM AUTHOR]

Background: Biofilm production in nonfermenting Gram-negative bacteria influences drug resistance. The aim of this work was to evaluate the effect of different antibiotics on biofilm eradication of clinical isolates of Achromobacter, Burkholderia, and Stenotrophomonas maltophilia. Methods: Clinical isolates were identified by matrix-assisted laser desorption ionization–time of flight mass spectrometry in a third-level hospital in Monterrey, Mexico. Crystal violet staining was used to determine biofilm production. Drug susceptibility testing was determined by broth microdilution in planktonic cells and biofilm cells. Results: Resistance in planktonic cells was moderate to trimethoprim-sulfamethoxazole, and low to chloramphenicol, minocycline, levofloxacin (S. maltophilia and Burkholderia), ceftazidime, and meropenem (Burkholderia and Achromobacter). Biofilm eradication required higher drug concentrations of ceftazidime, chloramphenicol, levofloxacin, and trimethoprim-sulfamethoxazole than planktonic cells (p < 0.05). Levofloxacin showed biofilm eradication activity in S. maltophilia, minocycline and meropenem in Burkholderia, and meropenem in Achromobacter. Conclusions: Drug resistance increased due to biofilm production for some antibiotics, particularly ceftazidime and trimethoprim-sulfamethoxazole for all three pathogens, chloramphenicol for S. maltophilia and Burkholderia, and levofloxacin for Burkholderia. Some antibiotics could be used for the treatment of biofilm-associated infections in our population, such as levofloxacin for S. maltophilia, minocycline and meropenem for Burkholderia, and meropenem for Achromobacter. [ABSTRACT FROM AUTHOR]

Virulence pathways in pathogenic bacteria are regulated by quorum sensing mechanisms, particularly biofilm formation through autoinducer (AI) production and sensing. In this study, the culture filtrate extracted from an edible mushroom, Agaricus subrutilescens , was fractionated to isolate a compound that inhibits biofilm formation. Four gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis , and Enterobacter cloacae) and two gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus) were used for the bioassay. The bioassay-guided chromatographic separations of the culture filtrate extract resulted in the isolation of the compound. Further, spectroscopic analyses revealed the identity of the compound as 2,2′-azoxybisbenzyl alcohol (ABA). The minimum inhibitory and sub-inhibitory concentrations of the compound were also determined. Azoxybisbenzyl alcohol was significantly effective in inhibiting biofilm formation in all tested bacteria, with half-maximal inhibitory concentrations of 3–11 µg/mL. Additionally, the bioactivity of ABA was confirmed through the bioassays for the inhibition of exopolysaccharide matrixes and AI activities. [ABSTRACT FROM AUTHOR]

Objectives To establish the epidemiology cut-off (ECOFF) values of eravacycline against Escherichia coli , Klebsiella pneumoniae , Enterobacter cloacae , Acinetobacter baumannii and Staphylococcus aureus , from a multi-centre study in China. Methods We collected 2500 clinical isolates from five hospitals in China from 2017 to 2020. The MICs of eravacycline were determined using broth microdilution. The ECOFF values of eravacycline against the five species commonly causing cIAIs were calculated using visual estimation and ECOFFinder following the EUCAST guideline. Results The MICs of eravacycline against all the strains were in the range of 0.004–16 mg/L. The ECOFF values of eravacycline were 0.5 mg/L for E. coli , 2 mg/L for K. pneumonia and E. cloacae , and 0.25 mg/L for A. baumannii and S. aureus , consistent with the newest EUCAST publication of eravacycline ECOFF values for the populations. No discrepancy was found between the visually estimated and 99.00% ECOFF values calculated using ECOFFinder. Conclusions The determined ECOFF values of eravacycline against the five species can assist in distinguishing wild-type from non-wild-type strains. Given its promising activity, eravacycline may represent a member of the tetracycline class in treating cIAIs caused by commonly encountered Gram-negative and Gram-positive pathogens. [ABSTRACT FROM AUTHOR]

Objectives The measurement of VOCs release in the headspace of a bacterial culture represents a new approach to rapidly assess antimicrobial susceptibility. Herein, we evaluated the diagnostic performance of the VITEK® REVEAL™ system directly from a collection of Gram-negative positive blood cultures. Materials and methods One hundred and twenty-eight positive blood cultures were included in the analysis (Enterobacterales, n  = 95; Pseudomonas aeruginosa , n  = 21; Acinetobacter baumannii complex, n  = 12). Samples were processed using VITEK® REVEAL™ according to the manufacturer's recommendations, and MICs of 22 antimicrobials were compared with those obtained using reference methods. Categorical agreement (CA), essential agreement (EA) and categorical errors were calculated. Results Overall, 2220 strain/antibiotic pair combinations were analysed. Of these, most were classified as resistant by reference antimicrobial susceptibility testing (1091/2220; 48.7%). The overall CA and EA were 97.6% and 97.7%, respectively. CA ranged from 97.5% in Enterobacterales to 97.9% in both P. aeruginosa and A. baumannii complex. The overall number of categorical discrepancies were: 18 very major errors (1.6%), 13 major errors (1.2%) and 22 minor errors (2.4%). EA ranged from 95.2% in P. aeruginosa to 98.1% in Enterobacterales. Screening test for ESBL phenotype was positive, indeterminate and negative in 13.7%, 32.6% and 27.4% of Enterobacterales isolates tested by both VITEK® REVEAL™ and the reference method, showing 100% CA. Conclusions VITEK® REVEAL™ represents a reliable tool to obtain antimicrobial susceptibility results of the main Gram-negative species directly from positive blood cultures with time to results of less than 8 h. [ABSTRACT FROM AUTHOR]

Background: Fusobacterium nucleatum (F. nucleatum) is an integral component of supra‐ and subgingival biofilms, especially more prevalent in subgingival areas during both periodontal health and disease. Aims: In this review, we explore the physical, metabolic, and genetic interactions that influence the role of F. nucleatum in the formation of mixed oral biofilms. The role of F. nucleatum in antibiotic resistance in oral biofilms was discussed and some therapeutic strategies were proposed. Methods: PubMed, Scopus, Google Scholar, and the Web of Science were extensively searched for English‐language reports. Results: F. nucleatum‐derived proteins such as RadD, Fap2, FomA, and CmpA are involved in direct interactions contributing to biofilm formation, while autoinducer‐2 and putrescine are involved in metabolic interactions. Both groups are essential for the formation and persistence of oral biofilms. This study highlights the clinical relevance of targeted interactions of F. nucleatum in supra‐ and subgingival oral biofilms. Conclusions: By focusing on these interactions, researchers and clinicians can develop more effective strategies to prevent biofilm‐related disease and reduce the spread of antibiotic resistance. Further research in this area is warranted to explore the potential therapeutic interventions that can be derived from understanding the interactions of F. nucleatum in oral biofilm dynamics. [ABSTRACT FROM AUTHOR]

This study aimed to construct a nanofibrous wound dressing composed of polyvinyl alcohol (PVA) and chitosan (CS) containing curcumin and Glycyrrhiza glabra root extract to inhibit infection and accelerate wound healing. Loading 10 wt% of G. glabra extract-curcumin (50:50) by electrospinng technique resulted in the formation of nanofibers (NFs) with diameter distribution 303 ± 38 and had a uniform and defect-free morphology. FTIR analysis confirmed the loading of the components without adverse interactions. Also, the results showed extremely high porosity, extraordinary liquid absorption capacity, and complete wettability. In addition, G. glabra extract-curcumin showed significant antioxidant activity and their release profile from NFs was continuous and sustained. Also, the prepared NF could inhibit the growth of both Gram-positive Saureus and Gram-negative E. coli strains. Wound healing evaluation in the infected animal model showed that the NFs caused full wound closure and accelerated skin regeneration. The studies on inhibiting the bacteria growth at the wound site also revealed complete inhibitory effects. Moreover, histopathology studies confirmed the complete regeneration of skin layers, formation of collagen fibers, and angiogenesis. Finally, PVA/CS NFs containing G. glabra extract-curcumin as a multifunctional bioactive wound dressing presented a promising approach for promoting the healing of infected wounds. [ABSTRACT FROM AUTHOR]

Euphorbia tirucalli, commonly known as the pencil cactus or milk bush plant, is used as an alternative medicine. The current study evaluated the phytochemical contents, antibacterial, anticandidal, and antisporicidal potential of the E. tirucalli methanolic extract. The antibacterial and anticandidal activity of E. tirucalli methanolic extract was determined by performing a disc diffusion assay, MIC, MBC, and MCC. The sporicidal activity was tested at different concentrations of extract and exposure times. Phytochemical analyses revealed the presence of alkaloids, saponins, cardiac glycosides, terpenoids, and tannins in E. tirucalli methanolic extract. Results demonstrated inhibition zones of the extract against Gram-positive bacteria were in range of 22.00-7.00 mm. Meanwhile, inhibition zones of the extract against Gram-negative bacteria were in range of 13.00-7.00 mm. All bacteria were inhibited with MIC values at 1.56-25.0 mg/ml and can be completely killed with MBC values of 20-200 mg/ml. Inhibition zones of E. tirucalli methanolic extract against Candida spp. were in the range of 20.00-8.00 mm. All Candida spp. were inhibited with MIC values at 1.56-100.00 mg/ml and MBC values of 100-300 mg/ml. All concentrations of the extract inhibited all Bacillus spp. spores at different exposure times. In conclusion, the methanolic extract of E. tirucalli exhibits antibacterial, anticandidal, and sporicidal activities. The findings indicated that the methanolic extract of E. tirucalli has good potential for prospective nature-based antimicrobial agents. [ABSTRACT FROM AUTHOR]

Klebsiella pneumoniae , a highly prevalent Gram-negative bacterium, is widely known for causing nosocomial infections, leading to various diseases including systemic infections and fever. In traditional medicine, Launaea nudicaulis (L.) Hook. f. (Asteraceae), is often used to alleviate fever caused by bacterial infections. This study aimed to assess the antibacterial efficacy of the key phytochemicals present in the extract of L. nudicaulis against a panel of K. pneumoniae isolates. Three main constituents were isolated from this plant: cichorin (1), methyl-3,5-di- O -caffeoylquinate (syn. macranthoin G) (2), and cynaroside (3). Among these compounds, macranthoin G demonstrated notable antibacterial activity, with minimum inhibitory concentrations ranging from 64 to 256 µg/mL. It was found to inhibit the growth of the tested isolates and significantly affect the integrity of their cell membranes in 65.2 % of cases. Moreover, it increased the permeability of both the inner and outer membranes in 60.87 % and 52.17 % of K. pneumoniae isolates, respectively. Docking studies revealed that it exhibited strong binding scores to LpxC and FabI enzymes, with significant interactions occurring with key amino acids in their active sites. Based on these findings, macranthoin G shows promise as a potential antimicrobial drug, warranting further research to validate its antimicrobial and pharmacokinetic properties. [Display omitted] • Three main components were isolated from Launaea naudicaulis. • The isolated compounds are cichorin, macranthoin G, and cynaroside. • Macranthoin G exhibited notable antibacterial action. • It impaired the inner and outer membrane integrity of Klebsiella pneumoniae. • It showed significant docking scores and interactions with LpxC and FabI enzymes. [ABSTRACT FROM AUTHOR]

Purpose: Severe burn injuries are often accompanied by infections and associated with high morbidity and mortality. This study aimed to compare the prevalence and clinical impact of bacteremia between patients receiving intensive care with and without burns. Methods: This single-center retrospective cohort study at the University Hospital Vienna, Austria, analyzed blood cultures from intensive care unit (ICU) patients with and without burns (2012–2022) to assess the prevalence of bacteremia, the associated pathogen distribution and the 60-day all-cause mortality. Results: In 1170 ICU patients, 303 with burns and 867 without, the prevalence of bacteremia was similar among patients with at least one blood culture (31/157 [19.7%] versus 44/213 [20.7%], OR [95%CI] = 0.95 [0.57–1.57]). Burn patients exhibited a significantly higher frequency of microbiological sampling (51.5% versus 24.5%, p < 0.001), resulting in a higher overall prevalence of bacteremia (10.2% versus 5.1%, p = 0.002). 16.2% of all identified pathogens were multidrug-resistant (MDR). The 60-day all-cause mortality was higher in patients with MDR pathogens than in patients without bacteremia (41.7% versus 10.6%, p = 0.026). Conclusion: Bacteremia prevalence was similar in burn and non-burn patients, with high rates of multidrug-resistant Gram-negative pathogens. The 60-day all-cause mortality was significantly higher in patients with MDR pathogens than in patients without bacteremia. [ABSTRACT FROM AUTHOR]

Infected fracture nonunions often require prolonged treatment and recovery courses. It is unclear whether the bacterial microbiome influences the time to healing as well as the eradication of infection. The goals of this study are (1) to assess the bacterial microbiome affecting infected nonunions and (2) to evaluate the effects of bacterial speciation on associated outcomes. Between 2006 and 2022, data from 551 adult patients from a single academic institution who presented with a fracture nonunion were analyzed retrospectively for infection. All patients underwent revision surgery with three sets of cultures obtained intra-operatively. Patients with significant intra-operative cultures were grouped into gram-positive and gram-negative culture cohorts. These patients were managed with a standardized protocol involving surgical debridement, nonunion site fixation, and culture-directed antibiotic treatment. Primary outcome was time to fracture union. Secondary outcomes included number of re-operations and eventual amputation or reconstructive surgery. 56 nonunion patients (10 %) were diagnosed with an infected nonunion (44 g-positive, 12 g-negative). Of these, 3 g-positive patients received an amputation or arthroplasty procedure prior to fracture union, and seven were lost to follow-up. There were no significant differences in age, gender, or nonunion site between cohorts. Most nonunions occurred in the lower extremity. The most common bacteria were staph species (54.3 %). 36 g-positive and 10 g-negative patients achieved fracture union. Time to union was on average 158.4 days longer in the gram-negative cohort—but did not reach statistical significance (446.8 days gram-positive, 662.3 days gram-negative, p = 0.69). There was no difference in re-operation rates (1.9 % gram-positive, 2.2 % gram-negative, p = 0.84). Patients with infected nonunions had wide-ranging bacterial contamination that were treated successfully using a standardized protocol. However, patients with any gram-negative culture trended toward a delay in time to union. [ABSTRACT FROM AUTHOR]

Infective endocarditis (IE) is a rare disease in children and is associated with significant morbidity and mortality. In recent years, significant changes have occurred in pediatric care that could have influenced the microbiology and presentation of IE. The aim of this work was to study epidemiological, microbiological, and clinical features of IE treated at a Pediatric Cardiac Surgery Reference Center located in Madrid (Spain) in a 10-years' period. A descriptive observational retrospective study was performed, including pediatric patients < 16 years old with definite or possible IE admitted to a reference center between January 2012 and December 2021. Thirty-two IE episodes were identified. Twenty-eight (87.5%) had congenital heart disease (CHD), 8 (25.0%) were preterm infants, 1 (3.1%) was immunocompromised and 6 (18.8%) had other chronic conditions; in 11 (34.4%) episodes more than one underlying condition was associated. In 20 (62.5%) episodes there was an indwelling central venous catheter (CVC); children with other comorbidities (preterm, immunocompromised, other chronic conditions) were more likely to have a CVC at diagnosis compared with patients with isolated CHD (p < 0.001). Thirty-six microbiological isolates were obtained in the 32 episodes; 4 (12.5%) episodes had 2 isolated microorganisms. Microbiological isolates were 20 (55.6%) Gram-positive bacteria (GPB), 10 (27.8%) non-HACEK Gram-negative bacteria (GNB), 1 (2.8%) HACEK-group bacterium, 4 (11.1%) fungi and 1 (2.8%) Coxiella burnetii. In 10 (31.3%) episodes, patients were colonized by multidrug-resistant bacteria (MDRB) and the etiology of IE in 3 (30.0%) of those episodes was the colonizing MDRB. MDRB colonization was associated with MDRB IE (p = 0.007). The most common complication was septic embolism: 11 (34.4%) episodes (9 pulmonary and 2 cerebral). In-hospital mortality was 6.3% (n = 2), all of them due to underlying conditions and not to IE or its complications. Clinical features and complications of IE episodes caused by non-HACEK GNB and those caused by GPB were compared, finding no statistically significant differences. Conclusion: Risk factors for developing IE, the proportion of embolic complications, and mortality rate were consistent with previously published findings. Proportion of IE cases attributed to non-HACEK GNB was higher than previously reported, suggesting an evolving epidemiology of IE. One-third of children colonized with MDRB subsequently developed IE caused by the same MDRB strains, so empirical coverage of MDRB organisms must be considered when IE is suspected in MDRB colonized patients. No significant differences in clinical features and complications were observed when comparing IE episodes caused by non-HACEK GNB and those caused by GPB, however larger cohort studies are needed. What is Known: • Infective endocarditis (IE) is a rare disease in children, associated with significant morbidity and mortality. • The main risk factor for developing IE in children is an underlying congenital heart disease. What is New: • With current changing epidemiology in pediatric IE, a higher proportion of IE caused by non-HACEK Gram-negative bacteria should be expected. • A significant percentage of children colonized by multidrug-resistant bacteria can develop an IE due to those bacteria. [ABSTRACT FROM AUTHOR]

Bacteria affect food quality in developing countries by spreading through contaminated soils and water. Antibiotics are used indiscriminately to eliminate Gram-positive and Gram-negative bacteria, with varying degrees of success. The use of nanomaterials with bactericidal properties can minimize the overuse of antibiotics. In this study, a two-dimensional p-type ZnO powder was successfully synthesized and its bactericidal properties were demonstrated. The XRD and Raman spectroscopy results indicated the presence of wurtzite-phase ZnO with Oi as the predominant native defect, resulting in p-type conductivity. SEM analysis confirmed the two-dimensional morphology, and optoelectronic characterization revealed a bandgap of 3.17 eV. Despite this high bandgap value, a plasmonic effect was generated on the surface of two-dimensional ZnO, which enhanced its bactericidal properties when the powders were in contact with bacteria. From an initial colony level of 5.5 × 105 CFU/mL, a significant decrease in the number of Gram-positive bacteria to 1.15 × 105 CFU/mL was observed, whereas the number of Gram-negative bacteria slightly increased to 1.45 × 106 CFU/mL. The observed inhibition rates were higher than those achieved with the broad-spectrum antibiotic, as validated in this study. The use of two-dimensional ZnO may provide a sustainable solution for the eradication of waterborne pathogens using visible light alone. [ABSTRACT FROM AUTHOR]

Introduction: Cefiderocol is a siderophore cephalosporin showing activity against various carbapenem-resistant Gram-negative bacteria (CR-GNB). No data currently exist about real-world use of cefiderocol in terms of types of therapy (e.g., empirical or targeted, monotherapy or combined regimens), indications, and patient characteristics. Methods: In this multicenter, prospective study, we aimed at describing the use of cefiderocol in terms of types of therapy, indications, and patient characteristics. Results: Cefiderocol was administered as empirical and targeted therapy in 27.5% (55/200) and 72.5% (145/200) of cases, respectively. Overall, it was administered as monotherapy in 101/200 cases (50.5%) and as part of a combined regimen for CR-GNB infections in the remaining 99/200 cases (49.5%). In multivariable analysis, previous isolation of carbapenem-resistant Acinetobacter baumannii odds ratio (OR) 2.56, with 95% confidence interval (95% CI) 1.01–6.46, p = 0.047] and previous hematopoietic stem cell transplantation (OR 8.73, 95% CI 1.05–72.54, p = 0.045) were associated with administration of cefiderocol as part of a combined regimen, whereas chronic kidney disease was associated with cefiderocol monotherapy (OR 0.38 for combined regimen, 95% CI 0.16–0.91, p = 0.029). Cumulative 30-day mortality was 19.8%, 45.0%, 20.7%, and 22.7% in patients receiving targeted cefiderocol for infections by Enterobacterales, A. baumannii, Pseudomonas aeruginosa, and any metallo-β-lactamase producers, respectively. Conclusions: Cefiderocol is mainly used for targeted treatment, although empirical therapies account for more than 25% of prescriptions, thus requiring dedicated standardization and guidance. The almost equal distribution of cefiderocol monotherapy and cefiderocol-based combination therapies underlines the need for further study to ascertain possible differences in efficacy between the two approaches. [ABSTRACT FROM AUTHOR]

Synthetic and untreated dyes discharged in wastewater effluents are a threat to an ecosystem. This study investigated dye degradation and detoxification efficiency of crude lignin peroxidase separately obtained from the cultures of Escherichia coli (LR0250096.1) and Pseudomonas aeruginosa (CP031449.2). The ability of the crude lignin peroxidase to degrade Malachite Green (MG), Remazol Brilliant Blue R (RBBR), Congo Red (CR), and Azure B (AZ) was evaluated at different operating conditions (enzyme, dye, and hydrogen peroxide concentrations; pH; temperature; and contact time). The ability of the degraded dyes to support the growth of bacteria was also investigated. The observed optimum operating conditions for lignin peroxidase extracts of the Escherichia coli on AZ were 20 mg/mL enzyme concentration, 50 mg/L dye, pH 7.0, temperature 50 °C, and 1.5 mM hydrogen peroxide within 20–50 min of incubation time and on MG were 20 mg/mL, 50 mg/L, 9.0, 30 °C, 0.1 mM, and 20 min, respectively. The enzyme extract from Pseudomonas aeruginosa on AZ demonstrated optimum operation conditions of 20 mg/mL, 50 mg/L, pH 9.0, 40 °C, 1.5 mM, and 50 min, respectively and on MG, they were 20 mg/mL, 50 mg/L, 6.0, 30 °C, 1.0 mM, and 20 min, respectively). The prepared enzyme showed an appreciable degradative effect on CR and RBBR compared with commercial lignin peroxidase. The degraded dyes were able to support the growth of two Gram-positive (Bacillus cereus and Staphylococcus aureus), and two Gram-negative (Proteus mirabilis and Escherichia coli) bacteria, indicating the efficiency and the potential use of the enzyme complexes in the clean-up of industrial dyes' waste. [ABSTRACT FROM AUTHOR]

Escherichia coli, a rod-shaped Gram-negative bacterium, is a significant causative agent of severe clinical bacterial infections. This study aimed to analyze the epidemiology of extended-spectrum β-lactamase (ESBL)-producing mcr-1 -positive E. coli in Shandong, China. We collected 668 non-duplicate ESBL-producing E. coli strains from clinical samples at Shandong Provincial Hospital between January and December 2018, and estimated their minimum inhibitory concentrations (MICs) using a VITEK® 2 compact system and broth microdilution. Next-generation sequencing and bioinformatic analyses identified the mcr-1 gene and other resistance genes in the polymyxin B-resistant strains. The conjugation experiment assessed the horizontal transfer capacity of the mcr-1 gene. Of the strains collected, 24 polymyxin B-resistant strains were isolated with a positivity rate of 3.59% and among the 668 strains, 19 clinical strains carried the mobile colistin resistance gene mcr-1, with a positivity rate of approximately 2.8%. All 19 clinical strains were resistant to ampicillin, cefazolin, ceftriaxone, ciprofloxacin, levofloxacin, and polymyxin B. Seventeen strains successfully transferred the mcr-1 gene into E. coli J53. All transconjugants were resistant to polymyxin B, and carried the drug resistance gene mcr-1. The 19 clinical strains had 14 sequence types (STs), with ST155 (n = 4) being the most common. The whole-genome sequencing results of pECO-POL-29_mcr1 revealed that no ISApl1 insertion sequences were found on either side of the mcr-1 gene. Our study uncovered the molecular epidemiology of mcr-1-carrying ESBL-producing E. coli in the region and suggested horizontal transmission mediated by plasmids as the main mode of mcr-1 transmission. [ABSTRACT FROM AUTHOR]

Effective disinfection processes have been investigated to provide pathogen-free drinking water. Due to growing concern about the potential negative effects of cyanobacteria in portable water, their treatment has gained more attention recently. This study aims to compare the inhibition efficiencies of Gram-negative bacteria (Escherichia coli; E. coli), Gram-positive bacteria (Bacillus subtilis; B. subtilis), and cyanobacteria (Microcystis aeruginosa; M. aeruginosa) using UV-C and solar irradiation, and their combination process with H2O2. Over 6 log removal value (LRV) of E. coli and B. subtilis was achieved within 1 min of UV-C irradiation (0.76 ± 0.02 mW/cm2). The solar and solar/H2O2 (50 mg/L) processes effectively reduced (>99%) both bacteria after 20 min. E. coli was more sensitive to hydroxyl radicals (•OH) compared to the B. subtilis due to a different cell wall structure, resulting in a 0.18–0.62 higher LRV than B. subtilis. However, solar-based processes did not effectively inhibit M. aeruginosa (>52.23%). The UV-C/H2O2 (50 mg/L) process showed the highest inhibition rate for M. aeruginosa (77.83%) due to the generation of •OH, leading to oxidative damage to cells. Additionally, chlorophyll-a (Chl-a) was measured to indicate cell lysis of M. aeruginosa. The removal rate of Chl-a extracted by viable M. aeruginosa was higher using the UV-C process (93.03%) rather than the UV-C/H2O2 process (80.95%), because UV-C irradiation could be most effective in damaging Chl-a. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the susceptibilities of pathogens isolated from cultures within the first 7 days of admission to the burn center and in the absence of healthcare-associated infection risk factors (HAIRF) to determine if current empiric antibiotics can be narrowed for refinement of an empiric antibiotic prescribing pathway according to the suspected source. A 3-year sample of patients and cultures was utilized in hopes of obtaining at least 30 isolates of the most common pathogens and their respective susceptibilities. A total of 268 clinically relevant (e.g. deemed infectious, versus colonization) pathogens were included in the final sample with sources including wounds, respiratory, blood, urine, and bone. Of the 268 pathogens included, 45% were Gram-negative and 69% of all pathogens were isolated from wound cultures. The existing empiric pathway, vancomycin plus cefepime, covered 98% and 84% of all Gram-positive and Gram-negative pathogens, respectively. In patients without HAIRF, coverage rose to 98% and 90%, respectively. Initial use of vancomycin and cefepime remains adequate for pathogens isolated within 1 week of admission in patients without HAIRF. For pneumonias, a narrower spectrum beta-lactam would not sufficiently cover respiratory pathogens isolated within the first week of admission. Regarding early wound infections, difficult-to-treat pathogens remain as a rare isolate of wound cultures within 1 week of admission. [ABSTRACT FROM AUTHOR]

Biofilm-associated bacterial infection brings serious threats to global public health owing to serious antibiotic resistance. It is urgently needed to develop innovative strategies to combat biofilm-associated bacterial infections. Polymyxins stand out as the last line of defense against Gram-negative bacteria. However, serious nephrotoxicity of polymyxins severely limits their clinical utility. Herein, a hypoxia-responsive liposome is designed as the nanocarrier of polymyxin B (PMB) to combat biofilms developed by Gram-negative bacteria. A metronidazole modified lipid (hypoxia-responsive lipid (HRLipid)) is synthesized to fabricate hypoxia-responsive liposomes (HRLip). PMB loaded hypoxia-responsive liposomes (HRL-PMB) is then prepared to mitigate the nephrotoxicity of PMB while preserving its excellent bactericidal activity. HRL-PMB shows very low hemolysis and cytotoxicity due to liposomal encapsulation of PMB. PMB can be readily released from HRL-PMB in response to hypoxic biofilm microenvironment, exerting its bactericidal activity to realize biofilm eradication. The excellent in vivo antibiofilm ability of HRL-PMB is confirmed by a Pseudomonas aeruginosa infected zebrafish model and a P. aeruginosa pneumonia infection model. Meanwhile, HRL-PMB can greatly reduce the nephrotoxicity of PMB after intravenous injection. The hypoxia-sensitive liposomes held great promise to improve the biosafety of highly toxic antibiotics while preserving their intrinsic bactericidal ability, which may provide an innovative strategy for combating biofilm-associated infections. [ABSTRACT FROM AUTHOR]