Methicillin-resistant Staphylococcus aureus: experience in a general hospital over four years

Abstract

From 1977 to 1981, 317 patients in a large general hospital became infected with methicillin- and gentamicin-resistant Staphylococcus aureus. The epidemic strain was characterized as bacteriophage type D11/83A/85, resistant to methicillin, cephalosporins and aminoglycosides, and contained a 24 megadalton plasmid which mediated gentamicin resistance. Spread within the hospital followed introduction of this organism into the general surgical and burn services and resulted from cross infection between patients. These services remained a reservoir of infection throughout the four-year period. Only 2% of hospital personnel carried methicillin-resistant S. aureus in their anterior nares, and only one of them was shown to be a long-term carrier. During the epidemic, there was no overall increase in serious staphylococcal infections, as reflected in bacteremias. As methicillin-resistant S. aureus increased, there was a reciprocal decrease in methicillin-sensitive S. aureus. Later, as methicillin-resistant S. aureus bacteremias decreased, methicillin-sensitive S. aureus bacteremias increased. Attempts to control the spread of the organism by containing infected patients on an isolation ward, or by placing all such infected patients in strict isolation, decreased the frequency of infections, but did not eliminate the organism. In 1980, the burn service was separated from the surgical service and moved into a new burn unit. Also, the five-bed rooms in the hospital were being converted to two-bed rooms. With only routine isolation precautions, the epidemic resolved over the next year, although the epidemic strain persists in the hospital.