High prevalence of Escherichia coli sequence type 131 among antimicrobial-resistant E. coli isolates from geriatric patients

• Published in: Journal of medical microbiology Vol. 64; no. Pt 3; pp. 243 - 247
• Main Authors: Ho, Pak-Leung, Chu, Yuki Pui-Shan, Lo, Wai-U, Chow, Kin-Hung, Law, Pierra Y, Tse, Cindy Wing-Sze, Ng, Tak-Keung, Cheng, Vincent Chi-Chung, Que, Tak-Lun
• Format: Journal Article
• Language: English
• Published: England 01.03.2015
• Subjects: Adolescent; Adult; Aged; Alleles; Anti-Infective Agents - pharmacology; Bacterial Typing Techniques; beta-Lactamases - genetics; DNA Primers - genetics; Drug Resistance, Bacterial - genetics; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - epidemiology; Escherichia coli Infections - microbiology; Escherichia coli Proteins - genetics; Female; Geriatrics; Humans; Male; Middle Aged; Prevalence; Species Specificity; Urinary Tract - microbiology; Urinary Tract Infections - epidemiology; Urinary Tract Infections - microbiology; Young Adult
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/jmm.0.000012

Previous work on the subclones within Escherichia coli ST131 predominantly involved isolates from Western countries. This study assessed the prevalence and antimicrobial resistance attributed to this clonal group. A total of 340 consecutive, non-duplicated urinary E. coli isolates originating from four clinical laboratories in Hong Kong in 2013 were tested. ST131 prevalence among the total isolates was 18.5 % (63/340) and was higher among inpatient isolates (23.0 %) than outpatient isolates (11.8 %, P<0.001), and higher among isolates from patients aged ≥65 years than from patients aged 18-50 years and 51-64 years (25.4 vs 3.4 and 4.0 %, respectively, P<0.001). Of the 63 ST131 isolates, 43 (68.3 %) isolates belonged to the H30 subclone, whereas the remaining isolates belonged to H41 (n = 17), H54 (n = 2) and H22 (n = 1). All H30 isolates were ciprofloxacin-resistant, of which 18.6 % (8/43) belonged to the H30-Rx subclone. Twenty-six (41.3 %) ST131 isolates were ESBL-producers, of which 19 had blaCTX-M-14 (12 non-H30-Rx, two H30-Rx and five H41), six had blaCTX-M-15 (five non-H30-Rx and one H30-Rx) and one was blaCTX-M-negative (H30). In conclusion, ST131 accounts for a large share of the antimicrobial-resistant E. coli isolates from geriatric patients. Unlike previous reports, ESBL-producing ST131 strains mainly belonged to non-H30-Rx rather than the H30-Rx subclone, with blaCTX-M-14 as the dominant enzyme type.