Japanese Journal of Veterinary Research;Volume 8, Number 1-4

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STUDIES ON BACTERIOPHAGE TYPING OF STAPHYLOCOCCI ISOLATED FROM BOVINE MILK : II. SOME OBSERVATIONS ON THE LYSOGENIC STRAINS

NAKAGAWA, Masaro

Permalink : http://hdl.handle.net/2115/4686
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Abstract

Lysogenicity was examined of 169 strains of coagulase-positive staphylococci which had been isolated from bovine milk samples. The results are summarized as follows. 1. Out of the 169 strains, 74 (43.8%) were proven to be phage carriers and 121 were susceptible to any of the phages. The lysogenic strains were detected with almost equal frequency from both of two groups of which the one consisted of phage-typable strains and the other of untypable ones. 2. The greater part of the carriers released phages which attack strains of types III and IV; about a half of the remaining part carried phages which were active on strains quite resistant to the phages of the International Series. 3. It was clearly recognized that more than a half of the phage-carrying milk strains, especially those attacking type IV cultures, were lysogenic toward none of the propagating strains of the International phages. 4. No significant correlation was observed in phage types between lysogenic strains and their indicators. 5. It was concluded that lysogenicity is not an important factor in an acquired phage resistance. 6. It was suggested in this paper that the phages carried by the lysogenic milk strains might be available for the typing of staphylococcal strains isolated from milk samples. The author wishes to express his cordial thanks to Prof. K. HIRATO, the chief of this department, for his kind direction and review of this paper.

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