Characterization of antimicrobial resistance patterns and integrons in human fecal Escherichia coli in Taiwan.
Two hundred and twenty-five fecal strains of Escherichia coli isolated from 109 non-hospitalized adults in 2006 were investigated for susceptibility to antibiotics and for the presence of integrons. High resistance rates in fecal strains of E. coli were observed for streptomycin (52.0%), ampicillin (50.2%), piperacillin (50.2%), trimethoprim/sulfamethoxazole (47.6%) and chloramphenicol (33.8%). Integrons were found in 31.5% (71/225) of the strains using an integrase gene PCR assay. Among 71 integrase-positive strains, 65 strains belonged to class 1 integrons, while the remainder belonged to class 2. Gene cassette patterns of class 1 integrons were further characterized by PCR and direct sequencing. Among those class 1 integrase-containing isolates, the integron cassette region was amplified by PCR in 40.0% (26 of 65) of isolates. Five different antimicrobial resistance gene cassette arrays were found in those isolates. These gene cassettes included those encoding resistance to trimethoprim (dfrV, dfrA7, dfrA12, dfrA17) and streptomycin (aadA1, aadA2, aadA5). Among those gene cassette arrays, dfrA12-orfF-aadA2 was found in 53.8% (14/26) of the isolates. These findings indicate that multidrug resistance of fecal flora is common in Taiwan and that integrons play an important role in resistance to trimethoprim and streptomycin in humans.
Yang
Chih-Man
CM
Hsin-Chu General Hospital, Department of Health, Hsinchu City, Taiwan, Republic of China.
Lin
Ming-Feng
MF
Lin
Chung-Hui
CH
Huang
Yi-Ting
YT
Hsu
Chia-Tse
CT
Liou
Ming-Li
ML
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics; D005243:Feces / Q000382:microbiology*; D006801:Humans; D032023:Integrons / Q000235:genetics*; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D013624:Taiwan
D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins