ファージ型別不能,多剤耐性の病巣分離ブドウ球菌と,その誘発ファージについての研究

Abstract

Increasing drug resistance and lowering phage typability are the characteristic features of staphylococci isolated at the Hokkaido University Hospital in the recent years. Of 285 strains obtained in 1966, only 105 (36.9%) were typable by means of the routine typing phages, with an occurrence of 63 strains (22.1%) with types 80/81. Seventy-seven of 180 phages derived from the untypable staphylococci lyzed one or more of the standard propagating strains, 46 (25.5%) of which were either PS 80 or PS 81. Cross lysis among the untypable staphylococci revealed 54 strains (30.0%) to be lysogenic.The phages from the untypable strains of staphylococci could be divided into the following three groups according to the host range. Two of the three groups were akin to each other and also to phages 80 and 81 (phages A and C); the third group was related to phage group III (phage B). Typing of the 180 untypable staphylococcal strains with these three phage varieties resulted in successful typing of 74 strains (41.1%), 70 of which were sensitive to the 80 and 81 related phages A and C. The fact suggests that a substantial portion of the untypable hospital strains of staphylococci may be lysogenized by phages related to phage 80 or 81 and hence phage resistant.In the present study, a close relationship was observed between the phage types of staphylococci and their drug resistance. Strains typable with the routine typing phages, except phages 80 and 81, were generally less resistant to ordinary antibiotics. Type 80/81, as well as the untypable strains of staphylococci, was more resistant, while such strains as lyzed by phages A and/or C were extremely resistant. The high and multiple drug resistance of the latter strains might have occurred through transduction by some special phages.