Streptococcus pyogenes hospital-acquired infection within a dermatological ward

Seventeen strains of Streptococcus pyogenes were isolated from 17 patients in the Dermatological Ward of Gunma University Hospital in Japan between June 1994 and March 1995. Of these 17 strains, 14 were isolated from the pus of skin infections, two from blood, and one from ascitic fluid. The strains showed the same minimum inhibitory concentrations; 4 mg/L of minomycin, 4 mg/L of ofloxacin and 16 mg/L of fosfomycin. T-antigen typing of the strains indicated they were T11 type. The restriction endonuclease digestion patterns of chromosomal DNA from the 17 strains were all identical. The vinyl sheet covering the bed on which the patients were treated was found to be contaminated with S. pyogenes. This strain showed identical characteristics to the strains derived from the patients. These results suggest that S. pyogenes was transmitted to patients in the Dermatological Ward from the surface of the vinyl sheet covering the bed.