Characteristics of CTX-M Extended-Spectrum β-Lactamase-Producing Escherichia coli Strains Isolated from Multiple Rivers in Southern Taiwan
ABSTRACTExtended-spectrum β-lactamase (ESBL)-producingEscherichia colisequence type ST131 has emerged as the leading cause of community-acquired urinary tract infections and bacteremia worldwide. Whether environmental water is a potential reservoir of these strains remains unclear. River water samples were collected from 40 stations in southern Taiwan from February to August 2014. PCR assay and multilocus sequence typing (MLST) analysis were conducted to determine the CTX-M group and sequence type, respectively. In addition, we identified the seasonal frequency of ESBL-producingE. colistrains and their geographical relationship with runoffs from livestock and poultry farms between February and August 2014. ESBL-producingE. coliaccounted for 30% of the 621E. colistrains isolated from river water in southern Taiwan. ESBL-producingE. coliST131 was not detected among the isolates. The most commonly detected strain wasE. coliCTX-M group 9. Among the 92 isolates selected for MLST analysis, the most common ESBL-producing clonal complexes were ST10 and ST58. The proportion of ESBL-producingE. coliwas significantly higher in areas with a lower river pollution index (P= 0.025) and regions with a large number of chickens being raised (P= 0.013). ESBL-producingE. colistrains were commonly isolated from river waters in southern Taiwan. The most commonly isolated ESBL-producing clonal complexes were ST10 and ST58, which were geographically related to chicken farms. ESBL-producingE. coliST131, the major clone causing community-acquired infections in Taiwan and worldwide, was not detected in river waters.