Analysis of integrons in clinical isolates of Escherichia coli in China during the last six years

• Published in: FEMS microbiology letters 2006-01, Vol.254 (1), p.75-80
• Main Authors: Su, Jianyu, Shi, Lei, Yang, Liansheng, Xiao, Zenghuang, Li, Xinhui, Yamasaki, Shinji
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; Antimicrobial agents; Bacteria; Bacteriology; Biological and medical sciences; Cassettes; China - epidemiology; Clinical isolates; drug resistance; Drug Resistance, Bacterial - genetics; E coli; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - isolation & purification; Escherichia coli Infections - epidemiology; Escherichia coli Infections - microbiology; Escherichia coli Proteins - genetics; Fundamental and applied biological sciences. Psychology; gene cassettes; Gene transfer; Genes; Genetics; Humans; Integrase; Integrases - genetics; Integrons; Microbial Sensitivity Tests; Microbiology; Molecular Sequence Data; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Phylogeny; Polymerase Chain Reaction - methods; Sequence Analysis, DNA
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2005.00025.x

Abstract A multiple PCR for the detection of the integrase genes of the three classes of integrons was carried out, and their gene cassettes were characterized in 111 clinical strains of Escherichia coli isolated in Guangzhou City, China during the last 6 years. IntI1 and intI2 genes were detected in 95 isolates (85.6%) and four isolates (3.6%), respectively. No intI3 gene was detected. Six different gene cassettes were found in these strains, and a high prevalence of dfr and aad genes was observed. The E. coli isolates that contained a 1664‐bp amplicon of dfrA17‐aadA5 in class 1 integron were found to be phylogenetically unrelated to each other by using the enterobacterial repetitive intergenic consensus PCR, as the cassette could be transferred to recipient strains, indicating that the gene cassettes might be disseminated in the clinical strains by a horizontal gene transfer. Therefore, it is important that guidelines for the prudent use of antimicrobial agents are adopted and surveillance programs are established.