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.
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.
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.
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.
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.
Accepted for publication October 24, 2014.
This work was supported by a research grant from Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan (VGHKS 102-040). The authors have no financial relationships relevant to this article. The authors have no other funding or conflicts of interest to disclose.
Drs. Ming-Fang Cheng and Wan-Ling Chen contributed equally to this study. Dr. Jiun-Ling Wang is alternate corresponding author: Department of Internal Medicine, E-Da Hospital No. 1, Yida Road, Yanchao District, Kaohsiung City 82445, Taiwan, ROC. E-mail: firstname.lastname@example.org.
Address for Correspondence: Chih-Hsin Hung, PhD, Department of Chemical Engineering and Institute of Biotechnology and Chemical Engineering, I-Shou University, No. 1, Sec. 1, Syuecheng Rd., Dashu District, Kaohsiung City 84001, Taiwan, ROC. E-mail:email@example.com.