Transmission of group A Streptococcus limited to healthcare workers with exposure in the operating room

BACKGROUND. Nosocomial transmission of group A Streptococcus (GAS) has been well described. A recent report of an outbreak investigation suggested that transmission can be extensive and that standard infection control measures may not be adequate to prevent transmission from patients with severe, invasive disease to healthcare workers (HCWs). OBJECTIVE. A case of pharyngitis in an HCW caring for a patient with GAS pharyngitis and necrotizing fasciitis prompted an investigation of the extent and risk factors for nosocomial transmission of GAS. SETTING. A 509-bed, tertiary care center in Portland, Oregon with 631,100 patient visits (hospital and clinic) and 11,500 employees in the year 2003. METHODS. HCWs with exposure to the index patient ("contacts") were identified for streptococcal screening and culture and completion of a questionnaire regarding the location and duration of exposure, use of personal protective equipment, and symptoms of GAS infection. RESULTS. We identified 103 contacts of the index patient; 89 (86%) submitted oropharyngeal swabs for screening and culture. Only 3 (3.4%) of contacts had a culture that yielded GAS; emm typing results and pulsed-field gel electrophoresis patterns of GAS isolates from 2 HCWs were identical to those for the isolate from the index patient. Both HCWs were symptomatic, with febrile pharyngitis and reported prolonged contact with the open wound of the patient in the operating room. CONCLUSIONS. In this investigation, nosocomial transmission was not extensive, and standard precautions provided adequate protection for the majority of HCWs. Transmission was restricted to individuals with prolonged intraoperative exposure to open wounds. As a result, infection control policy for individuals was modified only for HCWs with exposure to GAS in the operating room.