Characterization of antimicrobial resistance and class 1 integrons found in Escherichia coli isolates from humans and animals in Korea

• Published in: Journal of antimicrobial chemotherapy Vol. 55; no. 5; pp. 639 - 644
• Main Authors: Kang, Hee Young, Jeong, Young Sook, Oh, Jae Young, Tae, Sung Ho, Choi, Chul Hee, Moon, Dong Chan, Lee, Won Kil, Lee, Yoo Chul, Seol, Sung Yong, Cho, Dong Taek, Lee, Je Chul
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.05.2005; Oxford Publishing Limited (England)
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; antibiotics; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; Blotting, Southern; Conjugation, Genetic; Drug Resistance, Bacterial; Electrophoresis, Gel, Pulsed-Field; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - microbiology; gene cassettes; Humans; Integrons - genetics; Intestine, Large - microbiology; Korea - epidemiology; Medical sciences; Microbial Sensitivity Tests; Pharmacology. Drug treatments; plasmids; Plasmids - genetics; Poultry - microbiology; Swine - microbiology; Asia; Korea; Korea, Rep; Human; Drug susceptibility test; Escherichia coli; plasmids; Antimicrobial agent; gene cassettes; Characterization; Plasmid; Resistance; Antibiotic; Gene; Integron; Animal; Bacteria; Isolate; Antibacterial agent; antibiotics; Enterobacteriaceae
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dki076

Objectives: Antimicrobial resistance and class 1 integrons found in Escherichia coli isolates from humans and animals in Korea were characterized. Methods: E. coli isolates were examined for susceptibility to antimicrobial agents. Integrase genes were amplified. Gene cassette regions for classes 1 and 2 integrons were amplified and sequenced. Conjugal transfer and Southern hybridization were performed to determine the genetic localization of class 1 integrons. The clonal relationship of E. coli isolates carrying an identical cassette array was analysed by PFGE. Results: Commensal E. coli isolates from animals were highly resistant to commonly used antimicrobial agents such as tetracycline, sulfamethoxazole, streptomycin, ampicillin and carbenicillin. Integrons were most prevalent in commensal E. coli isolates from poultry (44%), followed by clinical isolates from humans (33%), commensal isolates from swine (23%) and humans (13%). dfrA17-aadA5, dfrA12-orfF-aadA2 and aadA1 were found most frequently in E. coli isolates from humans, poultry and swine, respectively. Class 1 integrons were mostly located in conjugative plasmids. E. coli isolates carrying an identical cassette array were phylogenetically unrelated. Conclusions: The use of antibiotics is strongly associated with antimicrobial resistance. E. coli isolates from different sources may select a specific gene cassette by antibiotic selective pressure, which results in differences in class 1 integrons. The horizontal transfer of class 1 integrons through conjugative plasmids seems to be responsible for wide dissemination of a particular type of class 1 integron.