A study of respiratory infection and sepsis caused by MRSA at Hokusho Central Hospital

At Hokusho Central Hospital, we studied the isolation rate of methicillin-resistant Staphylococcus aureus (MRSA) from 1985 to 1989; respiratory infection with MRSA, in 1989; and sepsis of MRSA, from 1988 to 1989. The isolation rate of MRSA from sputum increased from 0% in 1985 to 65.4% in 1989. MRSA was isolated mainly from elderly patients in a geriatric ward, with 55 of 67 strains (82%) being isolated from these patients in 1989. MIC80 of isolated MRSA strains was 0.01 microgram/ml to rifampicin, 0.02 microgram/ml to mynomycine, 3.13 micrograms/ml to vancomycin, 12.5 micrograms/ml to ofloxacin and 100 micrograms/ml to imipenem in 1989. One-third of the 60 isolated cases showed respiratory infections including 10 cases of pneumonia and 10 sepsis patients and 11 blood samples in 1988 and 1989, especially 92.9% of S. aureus isolated in 1989 was MRSA. Four of the 6 patients with respiratory infections of MRSA and 1 of the 3 patients with MRSA sepsis were treated successfully by a combination therapy of imipenem/cilastatin and cefazolin.