Development of a new set of phages as an epidemiological marker in Staphylococcus epidermidis causing nosocomial infections.

We describe the isolation of a new set of phages for typing Staphylococcus epidermidis. One hundred and eighty-two phages were obtained from S. epidermidis strains of human origin. Twelve phages were selected according to their potency and their lytic activity studied. Twenty phages of the Dean and Williams' set were also studied. Phage-typing was undertaken at 100 x RTD, 1000 x RTD and after heat treatment at 48 degrees C. When the two sets of phages were compared separately similar figures were obtained. When the two typing sets were combined, the percentage of typability for the 182 bacterial strains increased to 29.1% using 1000 x RTD and to 75.3% after heat treatment.