Characterization of thirteen Staphylococcus epidermidis and S. saprophyticus bacteriophages.

Thirteen bacteriophages of coagulase-negative staphylococci belonging to the Siphoviridae family (morphotype B1) were compared by seroneutralization kinetics, protein profiles, G + C content, DNA size and DNA/DNA hybridization. A previous classification into three morphological groups was confirmed. The Staphylococcus epidermidis phage group, although morphologically homogeneous, was heterogeneous by DNA/DNA hybridization (27 to 100% homology) and seroneutralization kinetics. Two new phage "species", STA1139 (STA for Staphylococcus) and STA1154A, corresponding to two morphological types of S. saprophyticus phages, were identified. Species STA1154A was particularly interesting because the size of its capsid, only 46 nm in diameter, and of its DNA, evaluated as 13 kbp, were smaller than those of other staphylococcal phages.