title: Phylogenetic origin and virulence genotype in relation to resistance to fluoroquinolones and/or extended-spectrum cephalosporins and cephamycins among Escherichia coli isolates from animals and humans.
abstract: In Escherichia coli infection, the implications of fluoroquinolone (FQ) and extended-spectrum cephalosporin plus cephamycin (AmpC) resistance for phylogenetic origin and virulence potential are undefined, as is the influence of ecological context on these associations. Accordingly, 106 E. coli isolates exhibiting FQ and/or AmpC resistance and 98 susceptible isolates were compared with regard to phylogenetic background and virulence profiles, stratified by host group (104 predominantly extraintestinal human isolates and 100 predominantly intestinal cattle and swine isolates). Although resistant isolates exhibited significant shifts in phylogenetic distribution and virulence profiles, human and animal isolates exhibited different phylogenetic shifts, and only among human isolates did resistance predict reduced virulence. Evidence for similar strains being resistant versus susceptible was scant. The O15:K52:H1 clonal group and the closely related "clonal group A" featured prominently among resistant and susceptible human isolates, respectively. Thus, in E. coli, antibiotic resistance predicts phylogenetic background and virulence potential in a complex, context-dependent fashion.
authors.affiliation: Medical Service, Veterans Affairs Medical Center, Minneapolis, MN 55417, USA. johns007@umn.edu
authors.forename: James R
authors.initials: JR
authors.lastname: Johnson
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kuskowski
authors.forename: Krista
authors.initials: K
authors.lastname: Owens
authors.forename: Abby
authors.initials: A
authors.lastname: Gajewski
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Winokur
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001426:Bacterial Proteins; D002417:Cattle; D018550:Cephalosporin Resistance; D002511:Cephalosporins / Q000494:pharmacology*; D002513:Cephamycins / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity*; D004927:Escherichia coli Infections / Q000382:microbiology; D024841:Fluoroquinolones; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D010802:Phylogeny; D019105:Random Amplified Polymorphic DNA Technique; D012703:Serotyping; D013552:Swine; D014774:Virulence / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D002511:Cephalosporins; D002513:Cephamycins; D024841:Fluoroquinolones; C048795:AmpC beta-lactamases; D001618:beta-Lactamases