[A clinical study of respiratory infection with methicillin-resistant Staphylococcus aureus (MRSA)]

We investigated patients with positive sputum for MRSA at Daido Hospital. The study was conducted from 1990 to 1991. The number of cases with positive sputum for MRSA is moderately increased. We classified 116 MRSA isolated cases into three groups, 67 cases of colonization with MRSA, 26 cases of suspected bronchopulmonary infection, and 23 cases of bronchopulmonary infection with MRSA. The coagulase types of MRSA were type II or type II + III. Examination of the susceptibility to antibiotics of MRSA showed that all MRSA strains were susceptible to sulfamethoxazole trimethoprim, arbekacin, and vancomycin. A few strains were resistant to rifampicin. There were no differences in coagulase types and susceptibility to antibiotics between the three groups. Bronchopulmonary infection with MRSA was frequently associated with underlying bronchopulmonary disease, whether malignant or not. Risk factors for MRSA bronchopulmonary infection could not be identified, but the prognosis of MRSA bronchopulmonary infection was poor in cases with higher grade of performance status. MRSA eradication rate in sputum after therapy was low, and was not improved by adding inhalation of antibiotics including vancomycin to systemic chemotherapy. This investigation demonstrates the importance of environmental prevention of MRSA infection in hospitals.