Streptococcal Invasive Disease - Group A, 2007

One hundred seventy-three cases of invasive group A streptococcal (GAS) disease (3.3 per 100,000 population), including 16 deaths, were reported in 2007, compared to 171 cases and 17 deaths in 2006. Ages of case-patients ranged from 6 days to 99 years (median, 50 years). Fifty-four percent of case-patients were residents of the metropolitan area. Fifty-nine (34%) case-patients had bacteremia without another focus of infection, and 31 (18%) case-patients had cellulitis with bacteremia. There were 22 (13%) cases of primary pneumonia and 14 (8%) cases of necrotizing fasciitis. Eighteen (10%) case-patients had septic arthritis and/or osteomyelitis, and three (2%) had streptococcal toxic shock syndrome (STSS) accompanied by another focus of infection. Thirteen (8%) case-patients were residents of long-term care facilities. Two facilities each had two case-patients.

The 16 deaths included eight cases of bacteremia without another focus of infection and three cases of pneumonia. The five remaining fatal cases had necrotizing fasciitis (2), peritonitis (1), and the type of infection was unknown for two deaths. The deaths occurred in persons ranging in age from 1 month to 95 years. For the 15 deaths in patients with known health histories, significant underlying medical conditions were reported for 13 of the case-patients.

Isolates were available for 160 (92%) cases, and 159 were subtyped using PFGE; 51 different molecular subtypes were identified. Twenty-five subtypes were represented by one isolate each; other subtypes were represented by two to 54 isolates each. No direct epidemiologic links were noted among cases with indistinguishable subtypes except for the two pairs of nursing home residents from the same facilities.

Isolates were available for 14 of the deaths and were distributed among six different PFGE subtypes. Eight deaths were attributed to the most common subtype, and two other deaths had indistinguishable subtypes.

• For up to date information see>> Group A Streptococcus (GAS)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2007