title: Clinical epidemiology and molecular analysis of extended-spectrum-β-lactamase-producing Escherichia coli in Nepal: characteristics of sequence types 131 and 648.
abstract: Recently, CTX-M-type extended-spectrum-β-lactamase (ESBL)-producing Escherichia coli strains have emerged worldwide. In particular, E. coli with O antigen type 25 (O25) and sequence type 131 (ST131), which is often associated with the CTX-M-15 ESBL, has been increasingly reported globally; however, epidemiology reports on ESBL-producing E. coli in Asia are limited. Patients with clinical isolates of ESBL-producing E. coli in the Tribhuvan University teaching hospital in Kathmandu, Nepal, were included in this study. Whole-genome sequencing of the isolates was conducted to analyze multilocus sequence types, phylotypes, virulence genotypes, O25b-ST131 clones, and distribution of acquired drug resistance genes. During the study period, 105 patients with ESBL-producing E. coli isolation were identified, and the majority (90%) of these isolates were CTX-M-15 positive. The most dominant ST was ST131 (n = 54; 51.4%), followed by ST648 (n = 15; 14.3%). All ST131 isolates were identified as O25b-ST131 clones, subclone H30-Rx. Three ST groups (ST131, ST648, and non-ST131/648) were compared in further analyses. ST648 isolates had a proportionally higher resistance to non-β-lactam antibiotics and featured drug-resistant genes more frequently than ST131 or non-ST131/648 isolates. ST131 possessed the most virulence genes, followed by ST648. The clinical characteristics were similar among groups. More than 38% of ESBL-producing E. coli isolates were from the outpatient clinic, and pregnant patients comprised 24% of ESBL-producing E. coli cases. We revealed that the high resistance of ESBL-producing E. coli to multiple classes of antibiotics in Nepal is driven mainly by CTX-M-producing ST131 and ST648. Their immense prevalence in the communities is a matter of great concern.
authors.affiliation: Department of Clinical Microbiology, Kathmandu University School of Medical Sciences, Dhulikhel, Nepal.
authors.forename: Jatan Bahadur
authors.initials: JB
authors.lastname: Sherchan
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan kayokohayakawa@gmail.com.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Hayakawa
authors.affiliation: Pathogenic Microbe Laboratory, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Miyoshi-Akiyama
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Ohmagari
authors.affiliation: Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Kirikae
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Nagamatsu
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Tojo
authors.affiliation: Department of International Medical Cooperation, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohara
authors.affiliation: Public Health Research Laboratory, Institute of Medicine, Tribhuvan University Teaching Hospital, Kathmandu, Nepal.
authors.forename: Jeevan B
authors.initials: JB
authors.lastname: Sherchand
authors.affiliation: Public Health Research Laboratory, Institute of Medicine, Tribhuvan University Teaching Hospital, Kathmandu, Nepal.
authors.forename: Sarmila
authors.initials: S
authors.lastname: Tandukar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D004926:Escherichia coli / Q000201:enzymology* / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D009390:Nepal / Q000453:epidemiology; D014774:Virulence / Q000235:genetics; D055815:Young Adult; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001618:beta-Lactamases
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