title: Prevalence and characteristics of ertapenem-resistant Klebsiella pneumoniae isolates in a Taiwanese university hospital.
abstract: This study was conducted to investigate the prevalence and characteristics of ertapenem-resistant (ETP-R) Klebsiella pneumoniae isolates at a Taiwanese hospital. The disk-diffusion tests revealed that the rate of ertapenem resistance among all isolates collected in 2008 was 13.5%, and the resistance rate among bloodstream isolates increased from 0% to 13.6% between 2001 and 2008. Eighty-two nonduplicate ETP-R isolates collected in 2008 were examined. Seventy-four (90.2%) isolates of them had extended-spectrum β-lactamases (CTX-M- and SHV-type), AmpC enzymes (DHA-1 and CMY-2), and IMP-8 metallo-β-lactamase alone or in combination, and an extremely high prevalence of fluoroquinolone resistance (95.1%) and plasmid-mediated quinolone resistance determinants (90.2%) were also observed. Eighteen ETP-R but imipenem-susceptible isolates were selected and compared with 18 imipenem-nonsusceptible isolates collected before 2008. Sequence analyses revealed genetic disruptions of OmpK36 in 11 imipenem-nonsusceptible and 6 imipenem-susceptible isolates, respectively, and OmpK35 disruptions in 10 isolates for both groups. For the isolates with intact ompK36, sodium dodecyl sulfate-polyacrylamide gel electrophoresis suggests decreased expression of OmpK36 in 5 of 7 imipenem-nonsusceptible isolates and 3 of 12 imipenem-susceptible isolates. In conclusion, the increasing prevalence of ertapenem resistance that was predominantly attributed to noncarbapenemase-mediated resistance mechanisms in K. pneumoniae is becoming a serious treat to patients in Taiwan.
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Jiunn-Jong
authors.initials: JJ
authors.lastname: Wu
authors.forename: Li-Rong
authors.initials: LR
authors.lastname: Wang
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Liu
authors.forename: Hung-Mo
authors.initials: HM
authors.lastname: Chen
authors.forename: Jing-Jou
authors.initials: JJ
authors.lastname: Yan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000235:genetics; D052978:Disk Diffusion Antimicrobial Tests; D016521:Electrophoresis, Gel, Pulsed-Field; D005838:Genotype; D006785:Hospitals, University; D006801:Humans; D007710:Klebsiella Infections / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology* / Q000635:transmission; D007711:Klebsiella pneumoniae / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D009154:Mutation; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012680:Sensitivity and Specificity; D013624:Taiwan; D018440:beta-Lactam Resistance / Q000187:drug effects / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D001618:beta-Lactamases