title: Molecular epidemiology and genetic diversity of fluoroquinolone-resistant Escherichia coli isolates from patients with community-onset infections in 30 Chinese county hospitals.
abstract: The high frequency of fluoroquinolone resistance in Escherichia coli is a feature of clinical bacteriology in China, where the molecular epidemiology and genetic characteristics of this resistance in county hospitals remain unclear. A total of 590 nonduplicate E. coli isolates from 30 county hospitals located across seven Chinese regions were examined for plasmid-mediated quinolone resistance (PMQR) genes and mutations in quinolone resistance-determining regions (QRDRs). Multilocus sequence typing (MLST) and phylogenetic analysis of fluoroquinolone-resistant isolates were used to determine their genetic relatedness. The ciprofloxacin resistance rate of community-onset E. coli was 51.2%, and at least one PMQR gene was carried by 220 (37.3%) isolates. These included qnr (3.7%), aac(6')-Ib-cr (19.7%), qepA (14.4%), and oqxAB (3.8%). Two novel oqxB mutants were identified and named oqxB20 and oqxB29. From 60 sequence types (STs) isolated, 5 novel STs (ST4499 to ST4503) were identified. ST1193 (7.9%) was the second most abundant ST among fluoroquinolone-resistant isolates (ST131 was the most common, with 14.6%), and this is the first report of it in China. This is also the first report of ST2115 and ST3014 isolates from human samples. Ciprofloxacin-resistant E. coli isolates fell mainly into phylogroups B2 and D. The rates of fluoroquinolone resistance and the prevalence of PMQR genes in community-onset E. coli isolates from Chinese county hospitals were high. The wide-ranging molecular epidemiology of E. coli isolates from scattered locations across China indicates that fluoroquinolone resistance evolved from different sources.
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Lina
authors.initials: L
authors.lastname: Zhao
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Beiwen
authors.initials: B
authors.lastname: Zheng
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Zeqing
authors.initials: Z
authors.lastname: Wei
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Shen
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Sujuan
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China.
authors.forename: Lanjuan
authors.initials: L
authors.lastname: Li
authors.affiliation: State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China xiao-yonghong@163.com.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Xiao
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D024841:Fluoroquinolones / Q000494:pharmacology*; D005798:Genes, Bacterial; D014644:Genetic Variation; D005838:Genotype; D006766:Hospitals, County; D006801:Humans; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D050505:Mutant Proteins / Q000235:genetics; D010802:Phylogeny; D010957:Plasmids / Q000032:analysis
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D024841:Fluoroquinolones; D050505:Mutant Proteins