Methicillin-resistant Staphylococcus aureus in nosocomial infections in the surgical ward and operating room.

In this study 214 strains of Staphylococcus aureus were isolated from clinical specimens on the surgical ward from 1983 to 1988 and in addition, 62 airborne strains were collected in the operating room. Highly methicillin-resistant strains of S.aureus (H-MRSA, MIC greater than 100 micrograms/ml) not detected in 1983 showed a significant increase in frequency by 1987 accounting for about 60% of MRSA (MIC greater than or equal to 12.5 micrograms/ml). Countermeasures instituted in 1987 such as the use of disinfectant chlorhexidine alcohol significantly decreased the frequency of MRSA and H-MRSA isolates in 1988. In our study of coagulase type, MRSA type IV strains were predominant until 1984, whereas after 1986 type II was prevalent. All airborne strains collected in the operating room were methicillin-sensitive S.aureus, with type VII currently epidemic. We therefore concluded that cross infection with MRSA took place on the surgical ward rather than in the operating room.