title: Drug susceptibility and molecular epidemiology of Escherichia coli in bloodstream infections in Shanghai, China, 2011-2013.
abstract: BACKGROUND
  Prevention and management of Escherichia coli bloodstream infections (EC-BSIs) have become increasingly complicated by antimicrobial resistance and rapid dissemination. We investigated the antimicrobial epidemiology and phylogenetic background of clinical E. coli isolates from patients with bloodstream infections in Shanghai from 2011 to 2013.
  
  
  METHODS
  Escherichia coli isolates causing bloodstream infections were consecutively collected between June 2011 and June 2013. Antimicrobial susceptibility testing was performed by disk diffusion. Drug resistance genes coding for extended-spectrum β-lactamases (ESBLs) and carbapenemases, and phylogenetic groups were detected by polymerase chain reaction. eBURST was used for multilocus sequence typing.
  
  
  RESULTS
  Of the strains 128 collected, 80 produced ESBLs. No carbapenem-resistant isolates were found. The resistance rates to penicillins, fluoroquinolone, folate pathway inhibitors, tetracyclines and second generation cephalosporins were high. Molecular analysis showed that CTX-M-14 (40/80) was the most common β-lactamase, followed by CTX-M-55 (17/80) and CTX-M-15 (14/80). Phylogenetic group B2 predominated (37.5%), but phylogenetic group D exhibited the highest rates of ESBL production. ST131 (17/128) was the most common sequence type, followed by ST69 (12/128) and ST648 (10/128).
  
  
  CONCLUSIONS
  The antimicrobial resistance rate was high among EC-BSI isolates, but amikacin, piperacillin-tazobactam and carbapenem could be options for empiric therapy. Genetic diversity showed no correlation with the nosocomial origin of the isolates.
authors.affiliation: Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China.
authors.forename: Sheng-Yuan
authors.initials: SY
authors.lastname: Zhao
authors.forename: Yan-Chun
authors.initials: YC
authors.lastname: Wang
authors.forename: Shu-Zhen
authors.initials: SZ
authors.lastname: Xiao
authors.forename: Xiao-Fei
authors.initials: XF
authors.lastname: Jiang
authors.forename: Xiao-Kui
authors.initials: XK
authors.lastname: Guo
authors.forename: Yu-Xing
authors.initials: YX
authors.lastname: Ni
authors.forename: Li-Zhong
authors.initials: LZ
authors.lastname: Han
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D003428:Cross Infection; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D055815:Young Adult; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase
keywords: Antimicrobial resistance; Escherichia coli; bloodstream infections; phylogenicity