Preliminary results of phage typing of coagulase-negative staphylococci with the set of typing phages of Pulverer and co-workers.

120 strains of Staphylococcus epidermidis isolated from clinical material were typed with the set of 16 test phages described by Pulverer et al. (1975). 58 (48%) strains were typable with RTD and additionally 12 strains with 100 times RTD. The pattern Ph10/U14/U16 was observed most common (36 strains), followed by the pattern U14/U16 (11 strains). One strain showed lysis reactions with all typing phages. With 61 strains phage U14 gave a lysis whereas phage U20 reacted only with 4 strains. The S. epidermidis phages were not specific for this species, at least some of these showed lysis reactions with S. aureus strains. The lysis pattern most often observed was Ph10/U14/U16. There was no correlation between the patterns given by the S. aureus test phages and those by the S. epidermidis phages.