title: Mechanisms of quinolone resistance in Escherichia coli and Salmonella: recent developments.
abstract: Fluoroquinolones are broad-spectrum antimicrobials highly effective for treatment of a variety of clinical and veterinary infections. Their antibacterial activity is due to inhibition of DNA replication. Usually resistance arises spontaneously due to point mutations that result in amino acid substitutions within the topoisomerase subunits GyrA, GyrB, ParC or ParE, decreased expression of outer membrane porins, or overexpression of multidrug efflux pumps. In addition, the recent discovery of plasmid-mediated quinolone resistance could result in horizontal transfer of fluoroquinolone resistance between strains. Acquisition of high-level resistance appears to be a multifactorial process. Care needs to taken to avoid overuse of this important class of antimicrobial in both human and veterinary medicine to prevent an increase in the occurrence of resistant zoonotic and non-zoonotic bacterial pathogens that could subsequently cause human or animal infections.
authors.affiliation: Antimicrobial Resistance and Molecular Epidemiology Unit, Laboratory of Enteric Pathogens, Health Protection Agency Centre for Infections, 61 Colindale Avenue, London NW9 5HT, UK. katie.hopkins@hpa.org.uk
authors.forename: Katie L
authors.initials: KL
authors.lastname: Hopkins
authors.forename: Robert H
authors.initials: RH
authors.lastname: Davies
authors.forename: E John
authors.initials: EJ
authors.lastname: Threlfall
mesh_terms: D000818:Animals; D027081:DNA Gyrase / Q000235:genetics; D027101:DNA Topoisomerase IV / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000662:veterinary; D029968:Escherichia coli Proteins / Q000235:genetics; D024841:Fluoroquinolones / Q000494:pharmacology; D006801:Humans; D010641:Phenotype; D010957:Plasmids / Q000235:genetics; D017354:Point Mutation; D015363:Quinolones / Q000494:pharmacology*; D012475:Salmonella / Q000187:drug effects* / Q000235:genetics; D012480:Salmonella Infections / Q000188:drug therapy; D012481:Salmonella Infections, Animal / Q000188:drug therapy
chemical_list: D029968:Escherichia coli Proteins; D024841:Fluoroquinolones; C485384:Qnr protein, E coli; D015363:Quinolones; D027101:DNA Topoisomerase IV; D027081:DNA Gyrase