title: High prevalence of Escherichia coli sequence type 131 among antimicrobial-resistant E. coli isolates from geriatric patients.
abstract: 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.
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors.forename: Pak-Leung
authors.initials: PL
authors.lastname: Ho
authors.affiliation: Department of Clinical Pathology, Tuen Mun Hospital, Hong Kong SAR, PR China.
authors.forename: Yuki Pui-Shan
authors.initials: YP
authors.lastname: Chu
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors.forename: Wai-U
authors.initials: WU
authors.lastname: Lo
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors.forename: Kin-Hung
authors.initials: KH
authors.lastname: Chow
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors.forename: Pierra Y
authors.initials: PY
authors.lastname: Law
authors.affiliation: Department of Clinical Pathology, Kwong Wah Hospital, Hong Kong SAR, PR China.
authors.forename: Cindy Wing-Sze
authors.initials: CW
authors.lastname: Tse
authors.affiliation: Department of Clinical Pathology, Princess Margaret Hospital, Hong Kong SAR, PR China.
authors.forename: Tak-Keung
authors.initials: TK
authors.lastname: Ng
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Hong Kong SAR, PR China.
authors.forename: Vincent Chi-Chung
authors.initials: VC
authors.lastname: Cheng
authors.affiliation: Department of Clinical Pathology, Tuen Mun Hospital, Hong Kong SAR, PR China.
authors.forename: Tak-Lun
authors.initials: TL
authors.lastname: Que
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D000890:Anti-Infective Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D017931:DNA Primers / Q000235:genetics; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D029968:Escherichia coli Proteins / Q000235:genetics; D005260:Female; D005853:Geriatrics; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013045:Species Specificity; D014551:Urinary Tract / Q000382:microbiology; D014552:Urinary Tract Infections / Q000453:epidemiology* / Q000382:microbiology; D055815:Young Adult; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000890:Anti-Infective Agents; D017931:DNA Primers; D029968:Escherichia coli Proteins; D001618:beta-Lactamases