Genotypic detection and molecular epidemiology of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a regional hospital in central Taiwan

Abstract

This study was conducted to detect the genes encoding extended-spectrum β-lactamases (ESBLs) and determine the epidemiological relatedness of 69 Escherichia coli and 33 Klebsiella pneumoniae isolates collected from a regional hospital in central Taiwan, mostly from inpatients (E. coli 87.0 %; K. pneumoniae 88.0 %). The phenotypes of these isolates were examined according to the combination disc method recommended by the Clinical and Laboratory Standards Institute. Most of the ESBL-producing E. coli and K. pneumoniae isolates (98.6 % and 97 %, respectively) could be detected using cefotaxime discs with and without clavulanate. Genotyping was performed by PCR with type-specific primers. CTX-M-14 type (53.6 %) was the most prevalent ESBL among E. coli isolates while SHV type (57.6 %) was the most dominant among K. pneumoniae isolates. Six E. coli and three K. pneumoniae isolates did not carry genes encoding ESBLs of types TEM, SHV, CTX-M-3, CTX-M-14, CMY-2 and DHA-1. The co-existence of two or more kinds of ESBL in a single isolate was common, occurring in 40.6 % and 72.7 % of E. coli and K. pneumoniae isolates, respectively. PFGE analysis revealed that ESBL producers isolated in this setting were genetically divergent.