EPIDEMIOLOGICAL AND GENETICAL STUDIES ON THE DRUG-RESISTANCE OF STAPHYLOCOCCI.
Final rept. 21 Jun 66-20 Jun 67,
GUNMA UNIV MAEBASHI (JAPAN) DEPT OF MICROBIOLOGY
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Surveys of staphylococcal strains, isolated from clinical sources in geographically scattered hospitals in Japan, disclosed the following facts 1 Triple TC.SM.SA, TC.PC.SA, PC.SM.SA and quadruple TC.PC.SM.SA resistant strains with reference to TC, SM, PC and SA, were manifest and they were restricted to specific phage group. 2 There are two types of resistant strains the first becomes resistant easily and consequently multiple resistant when a new drug is introduced, and consists largely of strains in phage group I containing phage type 8081. The second type remains single SA or double PC.SA, SM.SA resistant, and consists primarily of strains in group II and III. From the facts that all of the tested staphylococcal strains from clinical sources carry prophages and their drug resistance can be transduced to other strains by their prophages, the present author presents the hypothesis that transduction of drug resistance by prophage is mainly responsible for the acquisition of multiple resistance and wide distribution of multiple resistant strains. Genetic studies of drug resistance in staphylococci have disclosed the following facts 1 Resistance to TC is easily transduced at high frequencies by prophages obtained from multiple resistant strains. Resistance to SA and SM is jointly transduced with TC. Resistance to PC, the ability to form penicillinase PCase, is not transduced jointly with resistance to TC, SM and SA. Author