RT Journal Article SR Electronic(1) A1 Song, Wonkeun A1 Lee, Hyukmin A1 Lee, Kyungwon A1 Jeong, Seok Hoon A1 Bae, Il Kwon A1 Kim, Jae-Seok A1 Kwak, Hyo-SunYR 2009 T1 CTX-M-14 and CTX-M-15 enzymes are the dominant type of extended-spectrum β-lactamase in clinical isolates of Escherichia coli from Korea JF Journal of Medical Microbiology, VO 58 IS 2 SP 261 OP 266 DO https://doi.org/10.1099/jmm.0.004507-0 PB Microbiology Society, SN 1473-5644, AB This study was performed to assess the prevalence and genotypes of plasmid-borne extended-spectrum β-lactamases (ESBLs) and AmpC β-lactamases in Escherichia coli in Korea. A total of 576 isolates of E. coli was collected from 12 Korean hospitals during May and July 2007. A phenotypic confirmatory test detected ESBLs in 82 (14.2 %) of the 576 E. coli isolates. The most common types of ESBLs identified were CTX-M-14 (n=32) and CTX-M-15 (n=27). The prevalence and diversity of the CTX-M mutants, including CTX-M-15, CTX-M-27 and CTX-M-57, with significant hydrolytic activity against ceftazidime were increased. PCR experiments detected genes encoding plasmid-borne AmpC β-lactamases in 15/56 cefoxitin-intermediate or cefoxitin-resistant isolates, and the most common type of AmpC β-lactamase identified was DHA-1 (n=10). These data suggest that the incidence of ESBLs in E. coli has increased as a result of the dissemination of CTX-M enzymes in Korea. In addition, CTX-M-22, CTX-M-27 and CTX-M-57 have appeared in Korea., UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.004507-0