Characterization and Prevalence of Extended-Spectrumβ-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae isolates from 12 Korean Hospitals

Background : Presence of extended spectrum β-lactamase (ESBL)-producing gram-negative bacilli have been reported in Korea, but our understanding of the prevalence is limited. The aim of this study was to determine the nationwide prevalence and antimicrobial susceptibility of ESBL-producing Escherichia coli and Klebsiella pneumoniae, and to characterize the patients and sources. Methods : A total of 1,171 E. coli and 585 K. pneumoniae non-duplicate isolates were collected from 12 hospitals in September to December 1999. ESBL production was determined by National ommittee for Clinical Laboratory Standards methods using cefpodoxime, cefotaxime, ceftazidime, and aztreonam disk. Positive double disk synergy tests were considered ESBL producers. Results : ESBL-producing E. coli and K. pneumoniae isolates were detected from all 12 hospitals. The proportion of ESBL-produers was 9.8% (3.5-19.6%) of the E. coli and 25.6%(10-41.3%) of the K. pneumoniae isolates. The common soure of ESBL-producers was sputum (27.4%) and patients in intensive care unit (31.7%). ESBL-producing isolates were more often resistant to aminoglycosides and otrimoxazole. Conclusion : ESBL-producing E. coli and K. pneumoniae are widespread to all levels of Korean hospitals. ESBL-producers are more prevalent among isolates from urine and sputum and from intensive care unit patients. These organisms are more often resistant than the non-ESBL-producers to aminoglyosides and cotrimoxazole.ope