A5013787352- Antibiotic Resistance in Bacteria
- Pharmaceutical and Antibiotic Environmental Impacts
- Bacterial biofilms and quorum sensing
- Bacterial Genetics and Biotechnology
- Antibiotics Pharmacokinetics and Efficacy
- Escherichia coli research studies
- Infections and bacterial resistance
- Salmonella and Campylobacter epidemiology
- Bacterial Identification and Susceptibility Testing
- Vibrio bacteria research studies
- Phenothiazines and Benzothiazines Synthesis and Activities
- Bacteriophages and microbial interactions
- Microbial infections and disease research
- Mycobacterium research and diagnosis
- Antibiotic Use and Resistance
- Pneumonia and Respiratory Infections
- Helicobacter pylori-related gastroenterology studies
- Advancements in Transdermal Drug Delivery
- Microbial Natural Products and Biosynthesis
- Electrokinetic Soil Remediation Techniques
- Membrane Separation Technologies
- Dermatology and Skin Diseases
- Probiotics and Fermented Foods
- Pneumocystis jirovecii pneumonia detection and treatment
- Pesticide Residue Analysis and Safety
University of California, Davis
2024
Health Canada
2007-2023
Anhui Medical University
2023
Shandong First Medical University
2022
Shandong Provincial QianFoShan Hospital
2022
Shandong University
2022
University of California, Berkeley
2002-2005
Queen's University
1998-2004
University of California System
2004
The Mycobacterium smegmatis genome contains many genes encoding putative drug efflux pumps. Yet with the exception of lfrA, it is not clear whether these contribute to intrinsic resistance this organism. We showed first by reverse transcription (RT)-PCR that several genes, including lfrA as well homologues tuberculosis Rv1145, Rv1146, Rv1877, Rv2846c (efpA), and Rv3065 (mmr emrE), were expressed at detectable levels in strain mc(2)155. Null mutants each carrying an in-frame deletion then...
ABSTRACT Multidrug efflux pumps with a broad substrate specificity make major contribution to intrinsic and acquired multiple antibiotic resistance in Pseudomonas aeruginosa . Using genetically defined pump mutants, we investigated the involvement of three known systems, MexA-MexB-OprM, MexC-MexD-OprJ, MexE-MexF-OprN, organic solvent tolerance this organism. Our results showed that all systems are capable providing some level solvents such as n -hexane p -xylene. Expression MexAB-OprM was...
The clinical failure of antimicrobial drugs that were previously effective in controlling infectious disease is a tragedy increasing magnitude gravely affects human health. This resistance by pathogens often the endpoint an evolutionary process began billions years ago non-disease-causing microorganisms. environmental resistome, its mobilization, and conditions facilitate entry into are at heart current public health crisis antibiotic resistance. Understanding origins, evolution, mechanisms...
Abstract The performance of antimicrobial susceptibility testing (AST) bacteria and the interpretation AST results for isolated from animals are complex tasks which must be performed using standard published methodology overseen by experts in clinical microbiology consultation with pharmacologists. Otherwise, has significant potential errors mistakes. In this review, we provide guidance on how to correctly perform interpret results. Particular emphasis is placed various approved or...
ABSTRACT Clinical strains of Stenotrophomonas maltophilia are often highly resistant to multiple antibiotics, although the mechanisms resistance generally poorly understood. Multidrug (MDR) were readily selected by plating a sensitive reference strain organism individually onto variety including tetracycline, chloramphenicol, ciprofloxacin, and norfloxacin. Tetracycline-selected MDR typically showed cross-resistance erythromycin fluoroquinolones and, in some instances, aminoglycosides....
Of the six putative small multidrug resistance (SMR) family proteins of Pseudomonas aeruginosa, a protein encoded by PA4990 gene (emrE(Pae)) shows highest identity to well-characterized EmrE efflux transporter Escherichia coli. Reverse transcription-PCR confirmed expression emrE(Pae) in wild-type strain P. aeruginosa. Using isogenic emrE(Pae), mexAB-oprM, and/or mexB deletion mutants, contributions and MexAB-OprM system drug aeruginosa were assessed susceptibility test carried out...
ABSTRACT A homologue of the mexAB-oprM multidrug efflux operon Pseudomonas aeruginosa , smeABC was cloned from Stenotrophomonas maltophilia by using, as a probe, PCR product amplified this organism with primers based on mexB sequence. The genes were hyperexpressed in mutant strain displaying resistance to several antimicrobials, including aminoglycosides, β-lactams, and fluoroquinolones. Deletions smeC but not smeB compromised resistance, suggesting that SmeC contributed part another,...
ABSTRACT Stenotrophomonas maltophilia is an emerging nosocomial pathogen that displays high-level intrinsic resistance to a variety of structurally unrelated antimicrobial agents. Efflux mechanisms are known contribute acquired multidrug in this organism, and indeed, one such efflux system, SmeDEF, was recently identified. Still, the importance SmeDEF antibiotic S. had not yet been determined. Reverse transcription-PCR confirmed expression smeDEF genes wild-type , deletion smeE or smeF...
The MexAB-OprM multidrug efflux system exports a number of antimicrobial compounds, including beta-lactams. In an attempt to define more fully the range compounds exported by this system, and, in particular, determine whether beta-lactamase inhibitors were also accommodated pump, influence pump status (its presence or absence) on intrinsic antibacterial activities these and their abilities enhance beta-lactam susceptibility intact cells was assessed. MIC determinations clearly demonstrated...
ABSTRACT A Pseudomonas aeruginosa strain carrying an insertion of ΩHg interposon in the mexB gene ( ::ΩHg; K879) produced markedly reduced but still detectable levels OprM, product third mexAB-oprM multidrug efflux operon. By using a lacZ transcriptional fusion vector, promoter activity likely responsible for OprM expression ::ΩHg mutant was identified upstream oprM . Introduction gene, not mexAB genes, into P. multidrug-susceptible Δ increased resistance to quinolones, cephalosporins,...
ABSTRACT TonB couples the energized state of cytoplasmic membrane to operation outer receptors responsible for Fe(III) siderophore uptake across gram-negative bacteria. A tonB mutant Pseudomonas aeruginosa deficient in iron was shown present study be hypersusceptible a wide variety antibiotics, reminiscent phenotype mutants defective mexAB-oprM antibiotic efflux operon. This not related influences mutation on status cell, and indeed, intrinsic susceptibility expression were unaffected by...
The membrane fusion protein (MFP) component, MexA, of the MexAB-OprM multidrug efflux system P. aeruginosa is proposed to link inner (MexB) and outer (OprM) components this pump as a probable oligomer. A cross-linking approach confirmed in vivo interaction MexA MexB, while LexA-based assay for assessing protein-protein similarly multimerization. Mutations compromising contribution antibiotic resistance but yielding wild-type levels were recovered shown map two distinct regions within N-...
Abstract Antimicrobial resistance is a global One Health concern with critical implications for the health of humans, animals, and environment. Phenotypic methods bacterial culture antimicrobial susceptibility testing remain gold standards detection appropriate patient care; however, genotypic-based methods, such as PCR, whole genome sequencing, metagenomic genes conferring are increasingly available without inclusion quality or interpretation. Misleading test results may lead to...
Organic solvent-tolerant mutants of Pseudomonas aeruginosa selected in the presence hexane exhibited increased resistance to a variety structurally unrelated antimicrobial agents, including beta-lactams, fluoroquinolones, chloramphenicol, tetracycline, and novobiocin, phenotype typical nalB multidrug-resistant mutants. Western immunoblotting with antibodies specific components three known multidrug efflux systems P. demonstrated that displayed expression MexAB-OprM system decreased...
ABSTRACT OprM is the outer membrane component of MexA-MexB-OprM efflux system Pseudomonas aeruginosa . Multiple-sequence alignment this protein and its homologues identified several regions high sequence conservation that were targeted for site-directed mutagenesis. Of deletions which stably expressed, two, spanning residues G199 to A209 A278 N286 mature protein, unable restore antibiotic resistance in OprM-deficient strains P. Still, mutation conserved within these did not adversely affect...
Resistance to carbapenems in human pathogens is a growing clinical and public health concern. The are an antimicrobial class considered last-resort, they used treat infections caused by multidrug-resistant Enterobacterales, classified the World Health Organization as 'High Priority Critically Important Antimicrobials'. presence of carbapenem-resistant Enterobacterales (CREs) animal-origin concern because targeted studies Canadian retail seafood revealed carbapenem resistance small number...