title: Molecular characterization and antimicrobial susceptibility testing of Escherichia coli isolates from patients with urinary tract infections in 20 Chinese hospitals.
abstract: A total of 222 urinary Escherichia coli isolates from 20 tertiary hospitals in 15 different provinces and 4 municipalities in mainland China were characterized by antimicrobial susceptibility, phylogrouping, and the presence of plasmid-mediated quinolone resistance genes. A subset of 138 suspected extended-spectrum cephalosporinase (ESC) producers were examined for genes encoding cephalosporin resistance. Forty-three isolates harboring bla(CTX-M-14) or bla(CTX-M-15) were analyzed by pulsed-field gel electrophoresis (PFGE), and plasmids containing these genes were typed using PCR-based replicon typing (PBRT). Thirteen phylogroup B2 bla(CTX-M-14)- and bla(CTX-M-15)-positive isolates were analyzed by multilocus sequence typing (MLST). A frequent occurrence of resistance (>46%) was observed toward cephalosporins, gentamicin, and fluoroquinolones. Among the 222 isolates, 4 qnrS1, 4 qepA, and 16 aac(6')-Ib-cr genes were confirmed. Four major phylogroups (A, B1, B2, and D) and nontypeable isolates (NTs) were found among the isolates, with phylogroup D (54%) being the most common phylogroup. A total of 110 (80%) of the 138 screened isolates harbored bla(CTX-M) genes, with bla(CTX-M-14) (71%) and bla(CTX-M-15) (24%) being the most prevalent of these genes. Nine of the 13 CTX-M-15- or CTX-M-14-containing B2 isolates belonged to ST131. PFGE typing showed a high level of diversity, and plasmid analysis indicated a very large pool of different resistance plasmids mediating the spread of bla(CTX-M) genes in mainland China. An equally very high frequency of resistance and equally high levels of diversity in phylogroups, PFGE types, and plasmids were observed among community- and hospital-acquired E. coli isolates, indicating the presence of a large reservoir in the community and a long-term spread of cephalosporin resistance in China.
authors.affiliation: Department of General Surgery, Peking University First Hospital, Beijing 100034, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Cao
authors.forename: Lina M
authors.initials: LM
authors.lastname: Cavaco
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lv
authors.forename: Yun
authors.initials: Y
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Zheng
authors.forename: Pengyuan
authors.initials: P
authors.lastname: Wang
authors.forename: Henrik
authors.initials: H
authors.lastname: Hasman
authors.forename: Yucun
authors.initials: Y
authors.lastname: Liu
authors.forename: Frank M
authors.initials: FM
authors.lastname: Aarestrup
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002681:China; D016000:Cluster Analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D014644:Genetic Variation; D005838:Genotype; D006761:Hospitals; D006801:Humans; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D058885:Multilocus Sequence Typing; D010957:Plasmids / Q000032:analysis; D016133:Polymerase Chain Reaction; D014552:Urinary Tract Infections / Q000382:microbiology*; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases