title: Prevalence and characteristics of ertapenem-nonsusceptible Escherichia coli in a Taiwanese university hospital, 1999 to 2007.
abstract: The present study was conducted to investigate the prevalence and characteristics of ertapenem-nonsusceptible (ETP-NS) Escherichia coli in a Taiwanese university. A total of 9,722 isolates collected in 1999, 2003, 2005, and 2007 were examined. Overall, 1.0% of all isolates from 66 patients were interpreted as ETP-NS on the basis of the disk diffusion test result. Most of these isolates were clonally unrelated and showed low-level ertapenem resistance, the production of CMY-2 cephalosporinase (86.4%), and decreased expression of the OmpF (97.0%) and/or OmpC (56.1%) porins. No carbapenemase was detected. The decreased porin expression was associated with disruptions of ompF or ompC in only about one-third of the ETP-NS isolates. During the study period, the prevalence of ETP-NS strains increased from 0.1 to 1.7%, accompanying an increase (0.8 to 17.6%) in the prevalence of CMY-2 producers. Coexistent or pre-existing clonally related ertapenem-susceptible (ETP-S) E. coli isolates were identified in 47.0% of all case patients, and almost all of the ETP-S isolates had the same β-lactamases as the ETP-NS isolates. Our study results suggest the restricted use of extended-spectrum cephalosporins to hinder the emergence and prevalence of carbapenem resistance in E. coli, which may arise by the accumulation of multiple resistance determinants.
authors.affiliation: Department of Pathology, National Cheng Kung University Medical College and Hospital, 138 Sheng-Li Road, Tainan, 70428, Taiwan. jingjou@mail.ncku.edu.tw
authors.forename: J J
authors.initials: JJ
authors.lastname: Yan
authors.forename: J J
authors.initials: JJ
authors.lastname: Wu
authors.forename: C C
authors.initials: CC
authors.lastname: Lee
authors.forename: W C
authors.initials: WC
authors.lastname: Ko
authors.forename: F C
authors.initials: FC
authors.lastname: Yang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000378:metabolism; D015780:Carbapenems / Q000494:pharmacology / Q000627:therapeutic use; D002510:Cephalosporinase / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D000077727:Ertapenem; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology*; D006785:Hospitals, University; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009154:Mutation; D018272:Porins / Q000235:genetics; D013624:Taiwan / Q000453:epidemiology; D001618:beta-Lactamases / Q000378:metabolism; D047090:beta-Lactams / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; C113724:OmpC protein; C109237:OmpF protein; D018272:Porins; D047090:beta-Lactams; D002510:Cephalosporinase; D001618:beta-Lactamases; C063912:carbapenemase; D000077727:Ertapenem