STUDIES ON CAUSATIVE FACTORS FOR MRSA NOSOCOMIAL INFECTION

WITH REFERENCE TO ENVIRONMENTAL CONTAMINATION, CARRIER AND MEDICAL MANEUVERS

Abstract

Causative factors for nosocomial infection due to MRSA were analyzed and which factors played a more important role in the nosocomial infection was investigated. In the whole hospital MRSA was clinically isolated in 10 among 13 wards. As to enterotoxin types, there were 65.1% of AC type, 14.3% of B type, 7.9% of C type, and 12.7% of non-producing type. AC type was detected in 9 of the 10 wards, this type being the most epidemic strain in the hospital. However, among 92 medical staffs MRSA was detected from the nasal vestibule in only 8 staffs (8.7%), and 75% of them had B type. This result showed the different trend from clinical isolates. It was inferred that intranasal MRSA carriers (chronic carriage) did not so greatly contribute to MRSA epidemic. On the other hand, isolates from the fingers of medical staffs which can be thought as the transient carriage were AC type, which reflected the pattern of clinical isolates. AC type of MRSA represented 80.0% of all MRSAs such as aerobacteria isolated from the embironment. It is concluded that medical maneuvers and environmental contamintion may be the important causative factors for MRSA nosocomial infection.