[An outbreak of Streptococcus pyogenes infections in institutions for the mentally retarded in Greater Copenhagen 1995].

The largest reported outbreak of infections due to Streptococcus pyogenes, M-type 18, in recent years is described. Ninety persons at institutions for mentally retarded (73% residents) had infections due to the epidemic strain. Pharyngitis and scarlatina were the most common infections. Six patients died, five having a streptococcal toxic shock syndrome. During the outbreak an intensive surveillance was carried out together with improved infection control measures and prompt culturing of residents and employees before antimicrobial treatment. The primary outbreak was confined but a secondary outbreak could not be prevented. This was probably due to difficulties in implementing proper isolation precautions in this setting.