Premium
Drug Resistance of Enteric Bacteria
Author(s) -
Tanaka Tokumitsu,
Hashimoto Hajime,
Nagai Yutaka,
Mitsuhashi Susumu
Publication year - 1967
Publication title -
japanese journal of microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0021-5139
DOI - 10.1111/j.1348-0421.1967.tb00332.x
Subject(s) - tetracycline , chloramphenicol , drug resistance , microbiology and biotechnology , sulfanilamide , shigella , biology , bacteria , host factors , antibiotics , virology , genetics , virus , salmonella , biochemistry
Drug resistance of 3,000 Shigella strains isolated in 1965 were investigated. These strains originated from 10 City Hospitals and 4 Prefectural Health Centers, which are located in different parts of Japan. One hundred and seventy strains which were resistant to 4 drugs, chloramphenicol (CM), tetracycline (TC), dihydrostreptomycin (SM), and sulfanilamide (SA), were selected at random from these stock cultures in this laboratory and the distribution of R factors in these isolates was examined. It was found that the strains all harbored R factors which were capable of transferring drug resistance by usual conjugal process. Among the strains carrying R factors, 85 per cent harbored a single type of R factor and 15 per cent carried two types of R factor in a cell. The latter is called the hetero‐R state. Among the strains in the hetero‐R state, isolation of strains harboring both R (SM.SA) and R (TC.CM.SM.SA) factors was most frequent. It was found that 25 R (SM.SA) factors isolated from strains in hetero‐R had the genetic determinant i R − , while most of the R (TC.CM.SM.SA) factors isolated from natural sources were i R + . When two types of R factor, R (SM.SA) and R (TC.CM.SM.SA) derived from the same host cells, were brought together in a host cell by superinfection with both factors, they were found to exist stably in a host bacterium. These results confirmed the stable existence of both factors in Shigella strains isolated from dysenteric patients.