Phage typing has now proved to be a useful means for distinguishing different strains of Staphylococcus aureus. With the present prevalence of staphylococcal infections in hospitals, the advisability of phage typing is often debated. In making this decision, one may find it useful to bear certain facts in mind.
Phage typing has no prognostic value for the individual patient because it does not measure virulence. While strains of type 80/81 recently have caused many hospital infections, strains of other types have predominated at other times and in other countries. Any strain of staphylococcus which has produced infection must be regarded as potentially virulent.
Phage typing is solely an epidemiological tool. When applied together with documented clinical observations, it has value in (1) defining possible routes of spread in a circumscribed outbreak of disease, (2) maintaining surveillance of strains responsible for disease in a hospital or community, and (3) assessing distribution