In the 1950s, Staphylococcus aureus caused a worldwide epidemic of hospital acquired infections (nosocomial infections). By so doing, this bacterium forced nosocomial infections to be recognized as a major problem in the health care system. In that decade, it was discovered that Staphylococcus aureus is vectored by nurses in three different manners, and that carriage rates increase with length of clinical exposure to sources of the bacteria in the hospital environment.
Once subdued by antibiotics, multiple drug resistant strains of Staphylococcus aureus are again causing major nosocomial problems. In 1989, Cookson reported that a direct relationship exists between the degree (not length ) to which a health worker is exposed to a Staphylococcus aureus reservoir and the rate of carrier acquisition. Cookson also found that contrary to traditional thought, nurses became carriers without testing positive for hand contamination. This discovery reveals the versatility of Staphylococcus aureus, and it gives reason for more study dealing with the transmission of this important nosocomial pathogen.
Peterson, Mark, "Carriage Rates of the Nosocomial Pathogen Staphylococcus aureus in Hospital Workers" (1995). Senior Research Projects. 158.