In the preceding four papers of this series, we have presented evidence from four different hospital newborn services, which substantiates several hypotheses: (1) the presence of one particular strain of Staphylococcus aureus may interfere with the subsequent acquisition of another staphylococcal strain; (2) this phenomenon can be utilized to protect an infant against infection and disease caused by the so-called epidemic phage types; and (3) certain staphylococcal types are more pathogenic to infants than others.1-4
These studies were carried out in hospitals which cared for different population groups and engaged in a variety of nursery practices. The epidemiology of infectious disease in general is complex and perhaps even undefinable when several mutually independent factors operate simultaneously. It is thus
Table 1.—Protective Effect of Strain 502A on Subsequent Nasal Colonization With Other Types of Staphylococcus Aureus: Summary of Data from Three
Colonization with 80/81 or Staphylococci Other Than 502A