Staphylococcus aureus-strains of phage group II and their possible relation to animal staphylococci. 1. Antigenic properties, phage typing, and resistance to antibiotics.

Investigations carried out on 350 strains isolated from clinical materials and carriers revealed that among coagulase-positive staphylococci of phage group II two main serologic types predominated. The first (61,1%) was characterised by positive reaction with factor serum 263-2, the second (30,8%) one gave positive reaction with factor serum i1-2. The strains of type 263-2 contained as a rule polysaccharide A as well as polysaccharide 263, contrary to staphylococci belonging to type i1-2 which possessed polysaccharide A only. Both serologic types differed also epidemiologically, in phage typing and resistance to antibiotics. Staphylococci of serologic type 263-2 occurred in neraly all purulent lesions, they were more resistant to antibiotics than type i1-2 and prevailed in hospital environments. In phage-typing the differences between both serologic types were quantitative in character, with two being most outstanding, namely the prevalence of strains sensitive to phage 71 among staphylococci of serologic type 263-2 and of phage types 3A, and 3C as well as 3A, 3B, 3C among staphylococci of serologic type i1-2. There was no correlation between the susceptibility of strains to phage 71 and their virulence, the latter seemed to be connected with serologic type.