title: Molecular characteristics of extended-spectrum β-lactamase-producing Escherichia coli in a university teaching hospital.
abstract: The prevalence of extended-spectrum β-lactamases (ESBLs) has been increasing worldwide. Recently, a pandemic clone of Escherichia coli O25:H4, sequence type 131 (ST131), producing ESBL-type CTX-M-15 has been reported as a major problem. In this study, we investigated the molecular characteristics of 72 ESBL-producing E. coli isolates. We detected the ESBL blaCTX-M gene and nine virulence factor genes (papC, papEF, fimH, hlyA, iutA, sfa, eaeA, bfpA, and aggR) by PCR and DNA sequencing, plasmid replicon typing, phylogenetic grouping, repetitive-sequence-based PCR (rep-PCR), and multilocus sequence typing. All strains were positive for blaCTX-M. Twenty-two (30.6%) strains in CTX-M-1 group included 9 (12.5%) of CTX-M-15, 3 (4.2%) in CTX-M-2 group, and 47 (65.3%) strains in CTX-M-9 group. The CTX-M-15-producing E. coli O25:H4 ST131 was derived from phylogenetic group B2 and rep-PCR pattern d. The most prevalent virulence factor was fimH (72 strains; 100%) and the most common replicon type was the IncF type (65 strains; 90.3%). The CTX-M-9 group was significantly associated with the presence of papC and papEF [OR (95% CI)=9.22 (1.32-64.7), p=0.025] or hlyA [OR (95% CI)=5.57 (1.17-26.4), p=0.031]. In conclusion, we confirmed that CTX-M-15-producing E. coli O25:H4 ST131 has emerged in Japan and found significant virulence factors with CTX-M-9 group.
authors.affiliation: 1 Division of Infectious Diseases, Department of International Health, Kobe University Graduate School of Health Sciences , Kobe, Japan .
authors.forename: Kayo
authors.initials: K
authors.lastname: Osawa
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shigemura
authors.forename: Rika
authors.initials: R
authors.lastname: Shimizu
authors.forename: Ayaka
authors.initials: A
authors.lastname: Kato
authors.forename: Mari
authors.initials: M
authors.lastname: Kusuki
authors.forename: Takumi
authors.initials: T
authors.lastname: Jikimoto
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nakamura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshida
authors.forename: Soichi
authors.initials: S
authors.lastname: Arakawa
authors.forename: Masato
authors.initials: M
authors.lastname: Fujisawa
authors.forename: Toshiro
authors.initials: T
authors.lastname: Shirakawa
mesh_terms: D015373:Bacterial Typing Techniques / Q000379:methods; D004926:Escherichia coli / Q000235:genetics*; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology; D006784:Hospitals, Teaching; D006785:Hospitals, University; D006801:Humans; D007564:Japan; D008826:Microbial Sensitivity Tests / Q000379:methods; D010802:Phylogeny; D015995:Prevalence; D037521:Virulence Factors / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D037521:Virulence Factors; D001618:beta-Lactamases