ArticleAntimicrobial agents and chemotherapy2000
Evidence for active efflux as the primary mechanism of resistance to ciprofloxacin in Salmonella enterica serovar typhimurium.
Article in Antimicrobial agents and chemotherapy, 2000. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 71 papers.
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71 citing papers in PubMed, 226 citations in OpenAlex.
- A Comprehensive Review of the Multitarget Effects of Subinhibitory Concentrations of Essential Oils Against Salmonella.Comprehensive reviews in food science and food safety · 2026Review
- Gene Expression Analysis and Whole Genome Sequencing Reveal the Potential Mechanism of Ciprofloxacin Resistance in aVeterinary sciences · 2026Article
- Environmental conditions define the energetics of bacterial dormancy and its antibiotic susceptibility.Biophysical journal · 2023Article
- Assessment of multidrug-resistant profile, multi-locus sequence typing and efflux pump activity in Salmonella Typhimurium isolated from hospital sewage.World journal of microbiology & biotechnology · 2023Article
- Review
- Role of Efflux Pump-Mediated Antibiotic Resistance in Quorum Sensing-Regulated Biofilm Formation byPathogens (Basel, Switzerland) · 2022Article
- Uptake of Ozenoxacin and Other Quinolones in Gram-Positive Bacteria.International journal of molecular sciences · 2021Article
- Comparison of the Acinetobacter baumannii Reference Strains ATCC 17978 and ATCC 19606 in Antimicrobial Resistance Mediated by the AdeABC Efflux Pump.Antimicrobial agents and chemotherapy · 2021Article
- Susceptibility pattern of Salmonella enterica against commonly prescribed antibiotics, to febrile-pediatric cases, in low-income countries.BMC pediatrics · 2021Article
- Contribution of Different Mechanisms to Ciprofloxacin Resistance inFrontiers in microbiology · 2021Article
- A whole-genome screen identifies Salmonella enterica serovar Typhi genes involved in fluoroquinolone susceptibility.The Journal of antimicrobial chemotherapy · 2020Article
- Overexpression of RamA, Which Regulates Production of the Multidrug Resistance Efflux Pump AcrAB-TolC, Increases Mutation Rate and Influences Drug Resistance Phenotype.Antimicrobial agents and chemotherapy · 2020Article
- Tylosin exposure reduces the susceptibility of Salmonella Typhimurium to florfenicol and tetracycline.BMC veterinary research · 2020Article
- Antiquorum sensing and antibiofilm potential of biosynthesized silver nanoparticles of Myristica fragrans seed extract against MDR Salmonella enterica serovar Typhi isolates from asymptomatic typhoid carriers and typhoid patients.Environmental science and pollution research international · 2020Article
- Integrated Experimental and Computational Analyses Reveal Differential Metabolic Functionality in Antibiotic-Resistant Pseudomonas aeruginosa.Cell systems · 2019Article
- Evaluation of efflux pump activity of multidrug-resistantInfection and drug resistance · 2019Article
- Molecular and Physiological Characterization of Fluoroquinolone-Highly ResistantFrontiers in microbiology · 2019Article
- A Newly Discovered Drug Resistance GeneInfection and drug resistance · 2019Article
- Antibiotic-ResistantFoods (Basel, Switzerland) · 2018Review
- Role of Efflux Pumps in theFrontiers in microbiology · 2018Article
11 more citing papers are in PubMed but not listed here.
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4 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The occurrence of active efflux and cell wall modifications were studied in Salmonella enterica serovar Typhimurium mutants that were selected with enrofloxacin and whose phenotypes of resistance to fluoroquinolones could not be explained only by mutations in the genes coding for gyrase or topoisomerase IV. Mutant BN18/21 exhibited a decreased susceptibility to ciprofloxacin (MIC = 0.125 microg/ml) but did not have a mutation in the gyrA gene. Mutants BN18/41 and BN18/71 had the same substitution, Gly81Cys in GyrA, but exhibited different levels of resistance to ciprofloxacin (MICs = 2 and 8 microg/ml, respectively). None of the mutants had mutations in the parC gene. Evidence for active efflux was provided by a classical fluorimetric method, which revealed a three- to fourfold decrease in ciprofloxacin accumulation in the three mutants compared to that in the parent strain, which was annulled by addition of the efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone. In mutant BN18/71, a second fluorimetric method also showed a 50% reduction in the level of accumulation of ethidium bromide, a known efflux pump substrate. Immunoblotting and enzyme-linked immunosorbent assay experiments with an anti-AcrA antibody revealed that the resistance phenotype was strongly correlated with the expression level of the AcrAB efflux pump and suggested that decreased susceptibility to ciprofloxacin due to active efflux probably related to overproduction of this pump could occur before that due to gyrA mutations. Alterations were also found in the outer membrane protein and lipopolysaccharide profiles of the mutants, and these alterations were possibly responsible for the decrease in the permeability of the outer membrane that was observed in the mutants and that could act synergistically with active efflux to decrease the level of ciprofloxacin accumulation.
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