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

This study was conducted to detect the genes encoding extended-spectrumβ-lactamases (ESBLs) and determine the epidemiological relatedness of 69Escherichia coliand 33Klebsiella pneumoniaeisolates collected from a regional hospital in central Taiwan, mostly from inpatients (E. coli87.0 %;K. pneumoniae88.0 %). 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-producingE. coliandK. pneumoniaeisolates (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 amongE. coliisolates while SHV type (57.6 %) was the most dominant amongK. pneumoniaeisolates. SixE. coliand threeK. pneumoniaeisolates 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 % ofE. coliandK. pneumoniaeisolates, respectively. PFGE analysis revealed that ESBL producers isolated in this setting were genetically divergent.