Characterization of IncF plasmids carrying the bla^sub CTX-M-14^ gene in clinical isolates of Escherichia coli from Korea

The purpose of this study was to investigate the molecular epidemiology of CTX-M-14-producing Escherichia coli clinical isolates from Korea. A total of 138 non-duplicate E. coli clinical isolates showing reduced susceptibility or resistance to ceftazidime and/or cefotaxime were included in the study. Resistance genes, genetic environment, R plasmid size and replicon type, sequence type (ST) and XbaI-macrorestriction patterns were determined. Among 138 isolates, 35 were found to carry the ... gene. The ISEcp1 element was identified in the upstream region of the ... gene in 32 isolates. The ... gene was located on an IncF plasmid in 21 isolates, on an IncA/C plasmid in 1 isolate, on the chromosome in 8 isolates and on both the chromosome and an IncF plasmid in 5 isolates. The most prevalent ST was ST405 (n = 8), followed by ST354 (n = 4), ST38 (n = 3), ST69 (n = 3) and the intercontinental ST, ST131 (n = 3). PFGE and multilocus sequence typing experiments demonstrated no major clonal relationship among the CTX-M-14-producing isolates. The ... gene was probably mobilized by IncF plasmids, which can readily spread in E. coli, causing horizontal dissemination of the resistance gene in Korea. (ProQuest: ... denotes formulae/symbols omitted.)