Staphylococcus aureus cell surface: capsule as a barrier to bacteriophage adsorption.

Encapsulated Staphylococcus aureus strains M and Smith diffuse bound phage 84 and 52A much less efficiently than their unencapsulated counterparts, M variant and Smith compact. It is proposed that the capsule acts as a barrier excluding phage from interaction with their receptor (cell wall peptidoglycan and teichoic acid). Inefficient phage adsorption by encapsulated staphylococci may explain, in part, the poor phage typing of such strains.