Streptococcal Invasive Disease Group A, 2008

One hundred eighty-five cases of invasive group A streptococcal (GAS) disease (3.6 per 100,000 population), including 20 deaths, were reported in 2008, compared to 173 cases and 16 deaths in 2007. Ages of case-patients ranged from 1 year to 95 years (median, 48 years). Fifty-six percent of case-patients were residents of the metropolitan area. Fifty-four (29%) case-patients had bacteremia without another focus of infection, and 47 (25%) case-patients had cellulitis. There were 25 (14%) cases of primary pneumonia and 13 (7%) cases of necrotizing fasciitis. Fifteen (8%) case-patients had septic arthritis and/or osteomyelitis, and six (3%) had streptococcal toxic shock syndrome (STSS). Eleven (6%) case-patients were residents of long-term care facilities.

The 20 deaths included 10 cases of bacteremia without another focus of infection and 2 cases of pneumonia. The eight remaining fatal cases had cellulitis (5), abscess (1), otitis (1) and the type of infection was unknown for one death. The deaths occurred in persons ranging in age from 6 to 95 years. For the 20 deaths in patients with known health histories, significant underlying medical conditions were reported for 18 of the case-patients.

Isolates were available for 166 (90%) cases, and 163 were subtyped using PFGE; 64 different molecular subtypes were identified. Forty-five subtypes were represented by 1 isolate each; other subtypes were represented by 2 to 55 isolates each. No direct epidemiologic links were noted among cases with indistinguishable subtypes.

Isolates were available for 19 of the deaths and were distributed among 12 different PFGE subtypes. Six deaths were attributed to the most common subtype, and 2 other subtypes each accounted for 2 deaths.

• For up to date information see>> Group A Streptococcus (GAS)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2008