抄録
Shigella strains isolated in Japan from 1965 to 1967 were surveyed for drug resistance and distribution of R factors. Of 5, 875 strains tested, 5, 429 were resistant to either one or various combinations of four drugs, tetracycline (TC), chloramphenicol (CM), streptomycin (SM) and sulfanilamide (SA). Among these resistant strains, 80.3, 1.8, 2.2, and 15.7% were quadruply, triply, doubly and singly resistant, respectively. Fifty percent of these resistant strains were found to carry R factors which are capable of conjugal transfer. More than 50% of TC or CM resistant strains carried R factors, but in the remaining resistance type, R factors were rarely isolated. Only 3 and 17% carried R factors among SA and SM.SA resistant strains, respectively. The strains resistant to drugs other than the aforementioned four were very few; 0.9, 0.7 and 0.01% being resistant to aminobenzyl-penicillin (APC), nalidixic acid (NA) and kanamycin (KM), respectively. Conjugally transmissible NA resistance was not found among strains so far isolated and examined. About one third of APC resistance was transmissible. Among 9, 635 strains examined, one R factor possessing the KM resistance marker and 28R factors possessing the APC resistance marker were demon-strated. The R factor possessing the KM resistance marker was multiply resistant to 8 drugs; TC, CM, SM, SA, APC, KM, fradiomycin and paromomycin.
