title: Characterization of KPC-2-producing Escherichia coli, Citrobacter freundii, Enterobacter cloacae, Enterobacter aerogenes, and Klebsiella oxytoca isolates from a Chinese Hospital.
abstract: Twelve nonduplicated KPC-2-producing enterobacterial isolates, including three Escherichia coli, two Citrobacter freundii, two Enterobacter cloacae, four Enterobacter aerogenes, and one Klebsiella oxytoca, were collected from various clinical samples within 18 months (March 2011 to September 2012). Two of the 12 patients died from infections caused by KPC-2-producing pathogens, while the rest of the patients with KPC-2-producing pathogens improved or were cured. The majority of the clinical isolates exhibited a high-level of resistance to oxyimino-cephalosporins and carbapenems, and possessed self-transferable bla(KPC-2)-carrying plasmids with sizes ranging from 20 to 120 kb. Most isolates carried bla(CTX-M) and plasmid-mediated quinolone resistance genes, while some isolates produced 16S rRNA methylases (ArmA or RmtB). The genetic environment of bla(KPC-2) of most clinical strains was consistent with the genetic structure surrounding bla(KPC-2) on the plasmid pKP048, which contains an integration structure of a Tn3-based transposon and partial Tn4401 segment. Inserted fragments (truncated bla(TEM)) were detected upstream of the bla(KPC-2) gene for two E. aerogenes strains. In conclusion, the enterobacterial isolates exhibited sporadic emergence and did not arise by clonal spread at our hospital. The outcome of infections caused by KPC-producing enterobacterial isolates and their mortality were closely associated with the baseline condition of patients. The spread of bla(KPC-2) gene between different enterobacterial species in China was mainly mediated by horizontal transfer of the Tn3-based transposons and not the bla(KPC-2)-carrying plasmids.
authors.affiliation: 1 Department of Microbiology, Chinese PLA General Hospital , Beijing, China .
authors.forename: Yanping
authors.initials: Y
authors.lastname: Luo
authors.forename: Jiyong
authors.initials: J
authors.lastname: Yang
authors.forename: Liyan
authors.initials: L
authors.lastname: Ye
authors.forename: Lin
authors.initials: L
authors.lastname: Guo
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhao
authors.forename: Rong
authors.initials: R
authors.lastname: Chen
authors.forename: Yong
authors.initials: Y
authors.lastname: Chen
authors.forename: Xuelin
authors.initials: X
authors.lastname: Han
authors.forename: Jingya
authors.initials: J
authors.lastname: Zhao
authors.forename: Shuguang
authors.initials: S
authors.lastname: Tian
authors.forename: Li
authors.initials: L
authors.lastname: Han
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000627:therapeutic use; D015780:Carbapenems / Q000378:metabolism / Q000627:therapeutic use; D002511:Cephalosporins / Q000378:metabolism / Q000627:therapeutic use; D002681:China; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology* / Q000401:mortality / Q000635:transmission; D004251:DNA Transposable Elements; D024901:Drug Resistance, Multiple, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000472:pathogenicity; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000382:microbiology* / Q000401:mortality / Q000635:transmission; D015870:Gene Expression; D006761:Hospitals; D006801:Humans; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D016019:Survival Analysis; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D002511:Cephalosporins; D004251:DNA Transposable Elements; D008780:Methyltransferases; C047346:16S rRNA (adenine(1518)-N(6)-adenine(1519)-N(6))-dimethyltransferase; C491478:beta-lactamase KPC-2; D001618:beta-Lactamases