title: Dominance of CTX-M-type extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolated from patients with community-onset and hospital-onset infection in China.
abstract: OBJECTIVE
  To investigate CTX-M genotypes among extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) isolated from patients with community-onset and hospital-onset infections in China, their clonality and the distribution of CTX-M variants in different specimens of community-onset and hospital-onset infections.
  
  
  METHODS
  ESBL-EC isolates were collected from general hospitals from 2011 to 2012 in China. Broth microdilution method antimicrobial susceptibility testing of 16 antibiotics was performed. Clinical data from community-onset and hospital-onset infections due to ESBL-EC were analyzed. ESBL-encoding genes were amplified by PCR and sequenced, and multilocus sequence typing (MLST) was performed for a random selection of predominant CTX-M type strains identified.
  
  
  RESULTS
  A total of 1,168 ESBL-EC isolates were obtained from various clinical specimens, 41.7% of which were responsible for causing community-onset infections. The presence of urinary calculi was higher in community-onset infections, whereas malignancy, cardiovascular and cerebrovascular diseases, dementia, chronic renal disease, diabetes mellitus and surgical treatment were found to have higher proportions in hospital-onset infections. There was no significant difference in trauma between community-onset and hospital-onset infections. 96.2% of the isolates were detected to harbor blaCTX-M genes. blaCTX-M-1 group and blaCTX-M-9 group were detected at 40.7% and 48.7% respectively, and both positive group accounted for 10.6%. blaCTX-M-55 (24.8%) and blaCTX-M-15 (18.2%) were the major genotypes in blaCTX-M-1 group while blaCTX-M-14 (46.8%) was predominant in blaCTX-M-9 group. A comparison of blaCTX-M distribution in different specimens between ESBL-EC causing community-onset and hospital-onset infection showed no significant difference. A total of 229 isolates were tested for MLST. ST131 (14%) was the predominant type. ST648, ST405 and ST1193 were also detected.
  
  
  CONCLUSIONS
  Community-onset ESBL-EC has emerged as a common pathogen in China. CTX-M-14 is the most commonly encountered, CTX-M-55 and CTX-M-15 have spread rapidly. ST131 is the predominant clonal group, and the great diversity of CTX-M-producing isolates of E. coli has emerged in China.
authors.affiliation: State Key Laboratory of Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Xia
authors.affiliation: Department of Clinical Laboratory, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Zengguang
authors.initials: Z
authors.lastname: Huang
authors.affiliation: The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Xia
authors.affiliation: Department of Clinical Laboratory, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Rongchang
authors.initials: R
authors.lastname: Chen
authors.affiliation: Department of Clinical Laboratory, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Respiratory Disease, the First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhuo
mesh_terms: D002681:China / Q000453:epidemiology; D017714:Community-Acquired Infections / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics; D003428:Cross Infection / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000201:enzymology / Q000453:epidemiology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; D001618:beta-Lactamases