The Serological Differentiation of Staphylococcal Bacteriophages

Abstract

SUMMARY: By the use of anti-bacteriophage sera prepared in rabbits, thirty-nine staphylococcal phages were divided into six serological groups. The first group (A) comprised phages lysing coagulase-positive staphylococci of human origin. They were stable at 20° but inactivated at 49°. They multiplied in broth cultures containing sufficient tryptophan but rarely produced clearing of such cultures. The second group (B) lysed both bovine and human coagulase-positive staphylococci. They were markedly sensitive to heat and required growth factors present in the vitamin B complex. Group C comprised phages of ovine origin which were antigenically related to group B phages and also resembled them in their growth requirements. Group D comprised phage K, which lysed both coagulase-positive and negative staphylococci and was antigenically related only to phage W. Phage W belonged to group E and lysed only some coagulase-negative staphylococci. Group F was related in its general characters with the phages of group A. A staphylococcus was found carrying two serologically distinct phages, one of which was detected during the process of adaptation of a phage filtrate to a new propagating strain. Since many strains of staphylococci are lysogenic, lytic filtrates may contain contaminating phages which manifest themselves during adaptation. Adequate serological characterization of the phages used for typing and for investigations of phage-bacterium relationships and of apparent mutation is therefore necessary.