title: Quinolone resistance and correlation to other antimicrobial resistances in faecal isolates of Escherichia coli in Hong Kong.
abstract: In an attempt to assess the level of quinolone resistance and its association with other antimicrobial resistance in faecal Escherichia coli isolated from routine outpatient specimens in Hong Kong, ciprofloxacin-supplemented MacConkey agar was used to screen for resistant isolates. Antimicrobial susceptibility testing of the isolates was done by VITEK 2 and previous amplification-based methods were employed to characterize the genetic determinants behind some of the resistance phenotypes. One hundred and seventy-six (43%) of 409 specimens had quinolone-resistant E. coli isolated (199 isolates). Quinolone resistance was found to be associated with resistances to penicillins (>80%) and co-trimoxazole (69%). Nonsusceptibility to combinations of penicillins and clavulanic acid was above 20% and up to 50% for the aminoglycosides gentamicin and tobramycin. CTX-M-type extended-spectrum beta-lactamases were found responsible for most cephalosporin resistances but the transferable quinolone resistance determinant qnrA was not detected. Our data suggested that a high percentage of E. coli isolates as part of the alleged normal intestinal microflora in humans appeared to be resistant to quinolones. Co-resistance to various other frequently used antimicrobials was also observed. Transferable genetic determinants were found to be involved in some cases.
authors.affiliation: Microbiology Division, Public Health Laboratory Services Branch, Centre for Health Protection, Department of Health, Hong Kong, SAR, China. alf@dh.gov.hk
authors.forename: Yiu Wai
authors.initials: YW
authors.lastname: Chu
authors.forename: Terence K M
authors.initials: TK
authors.lastname: Cheung
authors.forename: Chi Ho
authors.initials: CH
authors.lastname: Wong
authors.forename: Grand K L
authors.initials: GK
authors.lastname: Tsang
authors.forename: Kenwai
authors.initials: K
authors.lastname: Lee
authors.forename: Stephen S Y
authors.initials: SS
authors.lastname: Lau
authors.forename: Kai Man
authors.initials: KM
authors.lastname: Kam
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects*; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000382:microbiology*; D005243:Feces / Q000382:microbiology*; D006723:Hong Kong; D006801:Humans; D015363:Quinolones / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones