An outbreak of group A streptococcal infection among health care workers

We describe the nosocomial transmission of group A Streptococcus species (GAS) from a single source patient to 24 health care workers (HCWs). DNA typing revealed that all of the isolates were identical to that of the source patient. The isolates were M type 1, positive for production of nicotine adenine dinucleotidase, and negative for opacity factor, all of which are factors reported to have a higher correlation with invasive disease. The 24 HCWs developed symptoms of pharyngitis less than or equal to4 days after exposure to the source patient. Nosocomial transmission occurred less than or equal to25 It after exposure to the source patient, before the institution of outbreak-control measures. A questionnaire was distributed to HCWs to help identify the factors responsible for the high attack rate among those who were exposed. Invasive GAS disease in a nosocomial setting can be highly transmissible. Rapid identification, early treatment, and adherence to infection-control practices may prevent or control outbreaks of infection.