title: Predominance of pHK01-like incompatibility group FII plasmids encoding CTX-M-14 among extended-spectrum beta-lactamase-producing Escherichia coli in Hong Kong, 1996-2008.
abstract: This study assessed the temporal changes in the molecular epidemiology of bacteremic Escherichia coli isolates producing CTX-M-14 in Hong Kong. Blood isolates from 1996 to 1998 (period 1, n = 50) and 2007 to 2008 (period 2, n = 117) were investigated by molecular methods. CTX-M-type ESBL was carried by 98.2% (164/167) of the isolates. In both periods, the CTX-M-9 group and CTX-M-14 allele were the predominant ESBL type. The major clones were found to change from ST68 and ST405 in period 1 to ST131, ST69, and ST12 in period 2. Among 65 CTX-M-14-producing plasmids investigated further, 54 had the FII replicon. Replicon sequence typing and plasmid polymerase chain reaction-restriction fragment length polymorphism showed that 79.6% (43/54) of the FII plasmid subset was similar to the completely sequenced plasmid, pHK01 (human urine, Hong Kong, 2004). These pHK01-like plasmids were found to have spread to the major clones (ST68, ST405, and ST131) and multiple singleton isolates of all 4 phylogenetic groups.
authors.affiliation: Department of Microbiology, University of Hong Kong, Pokfulam, Hong Kong, People's Republic of China. plho@hkucc.hku.hk
authors.forename: Pak Leung
authors.initials: PL
authors.lastname: Ho
authors.forename: Man Kiu
authors.initials: MK
authors.lastname: Yeung
authors.forename: Wai U
authors.initials: WU
authors.lastname: Lo
authors.forename: Herman
authors.initials: H
authors.lastname: Tse
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.forename: Eileen L
authors.initials: EL
authors.lastname: Lai
authors.forename: Kin Hung
authors.initials: KH
authors.lastname: Chow
authors.forename: Kelvin K
authors.initials: KK
authors.lastname: To
authors.forename: Wing Cheong
authors.initials: WC
authors.lastname: Yam
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology; D016009:Chi-Square Distribution; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D029968:Escherichia coli Proteins / Q000235:genetics; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D010957:Plasmids / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; C456080:beta-lactamase CTX-M-14; D001618:beta-Lactamases