Drug Resistance and Distribution of R Factors among Escherichia coli Strains

DOI Web Site Web Site Web Site PubMed 2 Citations 15 References
  • TANAKA Tokumitsu
    Department of Microbiology, School of Medicine, Gunma University
  • KOBAYASHI Akio
    Department of Microbiology, School of Medicine, Gunma University Clinical Laboratory, Chiba University School of Medicine
  • IKEMURA Kengo
    Department of Microbiology, School of Medicine, Gunma University Niigata Prefectural Institute of Health
  • HASHIMOTO Hajime
    Department of Microbiology, School of Medicine, Gunma University
  • MITSUHASHI Susumu
    Department of Microbiology, School of Medicine, Gunma University

Bibliographic Information

Other Title
  • Drug Resistance and Distribution of R Factors among <i>Escherichia coli</i> Strains

Search this article

Abstract

Three hundred and thirty-eight strains of Escherichia coli from clinical sources were examined for their drug resistances and R factors in 1971. With reference to four drugs, i.e., tetracycline(TC), chloramphenicol(CM), streptomycin(SM) and sulfanilamide(SA), the SA-resistant strains were isolated most frequently followed by SM-, TC- and CM-resistant ones in decreasing order. Among those resistant to the aforementioned four drugs, 20.3, 19.0, 7.7 and 18.3% were single-, double-, triple- and quadruple-resistant, respectively. The R factors were demonstrated at a frequency of 29.2% among these resistant strains. From the strains possessing quadruple-resistance, the conjugationally transferable R factors were demonstrated most frequently (60.5%) followed by triple- (59.1%), double(21.7%) and single-resistant strains (4.5%). The isolation frequencies of strains resistant to kanamycin (KM) and ampicillin (APC) were 1.5 and 4.7%, respectively; being fewer in numbers compared with those resistant to the four drugs. Strains resistant to cephaloridine, nalidixic acid, colistin. gentamicin C complex and furatridine were not isolated. Strains resistant to KM and APC were demonstrated mostly from those possessing multiple resistance with reference to the aforementioned four drugs. Among the strains carrying either APC- or KM-resistance, 76.9 and 100% respectively, were found to carry R factors, indicating that most of the APC- and KM-resistances were conferred by the R factors. Twenty percent of the R+ strains with reference to resistance to the four drugs carried two types of R factors in a cell, being in a hetero-R state, and 66.7% of the strains carrying R factors with APC- or KM-resistance were in a hetero-R state.

Journal

Citations (2)*help

See more

References(15)*help

See more

Keywords

Details 詳細情報について

Report a problem

Back to top