title: Molecular epidemiology of carbapenemase-producing Escherichia coli and the prevalence of ST131 subclone H30 in Shanghai, China.
abstract: The molecular characteristics and epidemiology of carbapenemase-producing Escherichia coli (CPEC) isolates from Shanghai, China, were investigated using 21 imipenem-resistant E. coli isolates obtained from a Shanghai teaching hospital from 2011 to 2014. The presence of bla KPC, bla IMP, bla VIM, bla OXA-48, and bla NDM was assessed by polymerase chain reaction (PCR) amplification and sequencing. CPEC isolates were characterized by the Etest®, multilocus sequence typing (MLST), and pulse-field gel electrophoresis (PFGE). Plasmids carrying resistance genes were analyzed by conjugation experiments, replicon typing, plasmid MLST (pMLST), S1 nuclease PFGE (S1-PFGE), and Southern hybridization. The genetic environment of the resistance genes was determined by PCR and sequencing. Among the 21 E. coli isolates, 16 produced carbapenemases; of these, ten isolates transferred carbapenemase-encoding plasmids to recipient bacteria. Nine of the 16 isolates were clonally related, and their PFGE patterns were designated type A. ST131 was the predominant sequence type (11 isolates, 68.8 %); the H30 subclone comprised 81.8 % of the ST131 strains. In all three isolates, bla IMP-4 was located on 50-kb IncN plasmids. All but two bla KPC-2 genes were carried on IncF plasmids of various sizes. Hence, both clone-spread and horizontal transfer mediated the dissemination of carbapenemase-producing genes in the Shanghai isolates.
authors.affiliation: Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197 Ruijin No. 2 Road, Shanghai, 200025, China.
authors.forename: F
authors.initials: F
authors.lastname: Zhang
authors.forename: D
authors.initials: D
authors.lastname: Zhu
authors.forename: L
authors.initials: L
authors.lastname: Xie
authors.forename: X
authors.initials: X
authors.lastname: Guo
authors.forename: Y
authors.initials: Y
authors.lastname: Ni
authors.forename: J
authors.initials: J
authors.lastname: Sun
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015139:Blotting, Southern; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics; D052978:Disk Diffusion Antimicrobial Tests; D004926:Escherichia coli / Q000145:classification* / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology*; D005838:Genotype; D006784:Hospitals, Teaching; D006801:Humans; D017720:Molecular Epidemiology; D058889:Molecular Typing; D010957:Plasmids / Q000032:analysis; D016133:Polymerase Chain Reaction; D015995:Prevalence; D017422:Sequence Analysis, DNA; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D001618:beta-Lactamases; C063912:carbapenemase