title: Emergence of extended spectrum-β-lactamase-producing Escherichia coli O25b-ST131: a major community-acquired uropathogen in infants.
abstract: BACKGROUND
  Escherichia coli sero-group O25b-sequence type 131 (O25b-ST131), a multidrug-resistant clonal group, is a significant pathogen in adults and children. This study investigated the genotyping and role of extended spectrum β-lactamase (ESBL)-producing E. coli O25b-ST131 and non-O25b-ST131 in urinary tract infections in infants.
  
  
  METHODS
  Clinical and laboratory data from 111 infants less than 1 year of age, who were hospitalized for urinary tract infections caused by ESBL-producing E. coli between 2009 and 2012 were collected. Polymerase chain reactions and multi-locus sequence typing were used to identify E. coli O25-ST131 clones. The gene blaCTX-M groups 1, 2 and 9, a specific polymerase chain reaction of CTX-M 14 and 15, were also determined in ESBL-producing E. coli isolates.
  
  
  RESULTS
  O25b-ST131 accounted for 65% of the 111 isolates, although 92 isolates belonged to the blaCTX-M group 9, of which most were CTX-M-14. Those with O25b-ST131 clones had similar risk factors, clinical features and outcomes as those with non-O25b-ST131. The E. coli O25b-ST131 isolates were more resistant to ciprofloxacin and gentamicin, but more susceptible to cefoxitin, minocycline and trimethoprim/sulfamethoxazole than the non-O25b-ST131 isolates. Most of the infants (78%) were previously healthy with no apparent risk factors.
  
  
  CONCLUSIONS
  E. coli O25b-ST131 is a major community-acquired uropathogen in the infant population. Regardless of O25b-ST131 or non-O25b-ST131 clones, CTX-M-14 accounts for majority of the ESBL genotype. The O25b-ST131 clone is not associated with more severe clinical disease, but it may make the diagnosis and selection of antimicrobials for treatment more challenging.
authors: From the *Department of Pediatrics, Veterans General Hospital-Kaohsiung, Kaohsiung, Taiwan, †School of Medicine, National Yang-Ming University, Taipei, Taiwan, ‡Department of Pediatrics, Pingtung Branch of Veterans General Hospital-Kaohsiung, Pingtung, Taiwan, §Department of Chemical Engineering and Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung, Taiwan, ¶Department of Internal Medicine, Veterans General Hospital-Kaohsiung, Kaohsiung, Taiwan, ‖School of Chinese Medicine for Post Baccalaureate, I-Shou University, Kaohsiung, Taiwan, and **Department of Internal Medicine, E-Da Hospital, Kaohsiung, Taiwan.
authors: Ming-Fang
authors: MF
authors: Cheng
authors: Wan-Ling
authors: WL
authors: Chen
authors: Wan-Yu
authors: WY
authors: Hung
authors: I-Fei
authors: IF
authors: Huang
authors: Yee-Hsuan
authors: YH
authors: Chiou
authors: Yao-Shen
authors: YS
authors: Chen
authors: Susan Shin-Jung
authors: SS
authors: Lee
authors: Chih-Hsin
authors: CH
authors: Hung
authors: Jiun-Ling
authors: JL
authors: Wang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D012189:Retrospective Studies; D014552:Urinary Tract Infections / Q000453:epidemiology / Q000382:microbiology*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases