The Identification of CTX-M-14, TEM-52, and CMY-1 Enzymes in Escherichia coli Isolated from the Han River in Korea

From water samples collected monthly between 2000 and 2001 from the Han River in Seoul, sixteen strains of Escherichia coli which confer resistance to at least 10 kinds of antimicrobial agents were isolated. From these isolates, 2 kinds of extended-spectrum beta-lactamases (ESBLs) and one plasmid-mediated AmpC beta-lactamase were detected; CTX-M-14 from 10 isolates, TEM-52 from 5 isolates, and CMY-1 from one isolate. Class 1 integron gene cassettes, such as aadA1, dfr12-orfF-aadA2, and dfr17-aadA5, were also detected and the integrons are the same as those found in E. coli isolated from swine, poultry, and humans in Korea. The result of this study indicated the importance of river water as a reservoir for antimicrobial resistance genes and resistant bacteria.