ソンネ菌のコリシン型とR因子型について

Abstract

The colicine type and drug-resistance pattern of R factor were investigated by using 514 strains of Shigella sonnei originated from 51 dysenteric patients in Gunma Prefecture over a 5-year period of 1958 to 1960, 1962, and 1966. The results obtained by Abbott and Shannon's method are summarized as follows.The strains isolated from 1958 to 1960 and in 1962 were divided into two colicine types, 6 and 12. Then 472 strains were isolated from 31 outbreaks in 1966 and divided into seven types: 6 (41.9%), 14 (32.3%), 12 (9.7%), 9A (6.5%), 4A (3.2%), 13A (3.2%), and 0 (3.2%), the last of which produced no colicine.This survey has disclosed that colicine type 14 has increased in frequency of isolation. It is well known that changes in colicine type are caused by superinfection of the col+ strain with other transmissible col factor. From these facts and from the epidemiological results, the increase in colicine type 14 may be accounted for by superinfection of col I to Shigella sonnei colicine type 6.The drug-resistance patterns of R factors of the Shigella strains isolated in 1966 were TC. CM. SM. SA in 81.8%, CM. SM. SA in 4.6%, and TC in 13.6%.It was found from these surveys that there was a close relationship between colicine type 14 and the quadruple (TC. CM. SM. SA) resistance pattern of R factors.In addition to these surveys, colicine typing was performed on 221 Escherichia coli strains by Abbott and Shannon's method. The results indicated that there were ten colicine types: 1A, 2, 3A, 4, 6, 7, 9, 11, 13, and 13A.