[Heterogeneity of natural populations of staphylococci]

It was revealed by the replique method that the Staphylococcus aureus populations were (in the primary cultures of material obtained from sick and healthy individuals) heterogeneous by phage type, pathogenicity signs and by the resistance to the antibacterial preparations. The extent of heterogeneity could be assessed by the number of variants and by the percentage of the most numerous variant. It differed in different groups of the patients examined. The extent of heterogeneity decreased in cloning the subcultures; this was in favour of the fact that heterogeneity of the primary cultures was caused chiefly by the entrance into the human organism of staphylococci of different biotypes. The replique method permitted to reveal the changes in the clonic structure of the staphylococcus population in the course of the disease, the effect of antibacterial therapy, the appearance of exogenous staphylococci, and their further fate.