[Analysis of methicillin-cephem resistant Staphylococcus aureus (MRSA) hospital infection and toxigenicity of MRSA].

MRSA infectious diseases were often observed in our ward including general, pediatric and neurosurgery during recent two years. Following items were investigated for analysing a prevalence of the infections; 1) the frequency of MRSA in Staphylococcus aureus isolates from clinical materials, 2) the monthly number of patients with MRSA infectious diseases, 3) the biologic types and the toxigenicity of MRSA isolates from clinical materials, nasal carriers and an environmental material in the ward. The results were as follows. 1) Methicillin-cephem resistant strain was determined in 204 of 247 Staphylococcus aureus isolates (83%). 2) Monthly registration showed a trend that an increased number of the patient in one unit was followed by an increase in other units. 3) Most of MRSA isolates were classified into type II coagulase and two kinds of strains were predominantly found in isolates from clinical materials by plasmid DNA analysis. Most of MRSA isolates had capabilities of producing type C enterotoxin and toxic shock syndrome toxin-1 (TSST-1). The results suggested that the frequent MRSA infectious diseases attributed to hospital infection. Since hospital infection of virulent MRSA may cause serious infectious diseases, much concern to inhibit the spread of this organism should be required.