ArticleInternational journal of antimicrobial agents2018
Chromosomal mutations that accompany qnr in clinical isolates of Escherichia coli.
Article in International journal of antimicrobial agents, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers.
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Who cites it
12 citing papers in PubMed, 22 citations in OpenAlex.
- Determination of frequency of spontaneous resistance for gepotidacin and levofloxacin against a collection of gram-positive and gram-negative organisms.Antimicrobial agents and chemotherapy · 2026Article
- First Pandemic blaCTX-M-8-Producing ST224 E. coli in Brazilian Sheep: Resistance and Genomic Traits.EcoHealth · 2026Article
- Resistance Mechanisms of Fluoroquinolone inAntibiotics (Basel, Switzerland) · 2025Article
- Determinants of Antibiotic Resistance and Virulence Factors in the Genome ofAntibiotics (Basel, Switzerland) · 2024Article
- Unusual and Unconsidered Mechanisms of Bacterial Resilience and Resistance to Quinolones.Life (Basel, Switzerland) · 2024Review
- Prevalence of Plasmid-Mediated Quinolone Resistance (PMQRs) Determinants and Whole Genome Sequence Screening of PMQR-ProducingInternational journal of molecular sciences · 2022Article
- The molecular mechanisms of fluoroquinolone resistance found in rectal swab isolates of Enterobacterales from men undergoing a transrectal prostate biopsy: the rationale for targeted prophylaxis.Annals of clinical microbiology and antimicrobials · 2021Article
- Interactions of Polymyxin B in Combination with Aztreonam, Minocycline, Meropenem, and Rifampin against Escherichia coli Producing NDM and OXA-48-Group Carbapenemases.Antimicrobial agents and chemotherapy · 2021Article
- Limited Multidrug Resistance Efflux Pump Overexpression among Multidrug-Resistant Escherichia coli Strains of ST131.Antimicrobial agents and chemotherapy · 2021Article
- A whole-genome screen identifies Salmonella enterica serovar Typhi genes involved in fluoroquinolone susceptibility.The Journal of antimicrobial chemotherapy · 2020Article
- Transferable Mechanisms of Quinolone Resistance from 1998 Onward.Clinical microbiology reviews · 2019Review
- Effects of a previously selected antibiotic resistance on mutations acquired during development of a second resistance in Escherichia coli.BMC genomics · 2019Article
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Authors and funding
3 authors at 2 institutions in 1 country.
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Abstract
We examined 13 qnr-positive and 14 qnr-negative clinical isolates of Escherichia coli for mutations previously seen in a qnr-containing laboratory strain exposed to supra minimum inhibitory concentrations (MICs) of ciprofloxacin. Among the qnr-positive strains, those with ciprofloxacin MICs of ≥ 2 µg/mL had at least one mutation in gyrA. Mutations in parC were present in strains with a ciprofloxacin MIC of ≥ 128 µg/mL. The 6 most ciprofloxacin-resistant strains contained additional plasmid-mediated quinolone resistance determinants. aac(6')-Ib-cr was found in 5 of the 6 strains. Eleven of the 13 strains had alterations in MarR, 9 in SoxR, and 5 had mutations in AcrR. All had elevated expression of at least one efflux pump gene, predominantly acrA (92% of the strains), followed by mdtE (54%) and ydhE (46%). Nine had functionally silent alterations in rfa, two had mutations in gmhB, and one of these also had a mutation in surA. An E. coli with ciprofloxacin MIC of 1024 µg/mL contained 4 different plasmid-mediated quinolone resistance determinants as well as gyrA, parC, parE and pump overexpression mutations. Nine of the 14 qnr-negative strains had mutations in topoisomerase genes with a ciprofloxacin MIC of 0.25 to 256 µg/mL. The three most resistant strains also had mutations in parE. Twelve had alterations in MarR, 10 in SoxR and 5 in AcrR. Ten of the 14 strains had elevated expression of efflux pumps with acrA (71.4%), followed by ydhE (50%) and mdtE (14.3%). A diversity of resistance mechanisms occurs in clinical isolates with and without qnr genes.
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