Streptococcal Invasive Disease - Group A, 2004

One hundred forty-six cases of invasive group A streptococcal (GAS) disease (2.9 per 100,000 population), including 18 deaths, were reported in 2004, compared to 181 cases and 22 deaths in 2003. Ages of case-patients ranged from newborn to 100 years (mean, 50 years). Fifty-eight percent of case-patients were residents of the Twin Cities metropolitan area. Forty-seven (32%) case-patients had bacteremia without another focus of infection. There were 14 (10%) cases of primary pneumonia and 16 (11%) cases of necrotizing fasciitis. Thirteen (9%) case-patients had septic arthritis and/or osteomyelitis, and two (1%) had streptococcal toxic shock syndrome (STSS). Fifteen (10%) case-patients were residents of 14 long-term care facilities. One facility had two case-patients with indistinguishable PFGE subtypes whose illness onsets were 4 days apart.

The 18 deaths included eight (44%) cases of bacteremia without another focus of infection, three (17%) cases of necrotizing fasciitis, and two (11%) cases of pneumonia. One case-patient had STSS and one case had puerperal sepsis. The remaining fatal cases had bacteremia with another focus of infection, including two (11%) with cellulitis, and one (6%) with both pneumonia and cellulitis. The deaths occurred in persons ranging in age from three to 92 years. For the 15 deaths in patients with known health histories, significant underlying medical conditions were reported for all but three of the cases.

Isolates were available for 133 (91%) cases, of which all were subtyped using PFGE; 56 different molecular subtypes were identified. Thirty-nine subtypes were represented by one isolate each; other subtypes were represented by two to 42 isolates each. No epidemiologic links were noted among cases with indistinguishable subtypes, except for the two cases from the same long-term care facility as described previously.

The deaths were distributed among 10 different PFGE subtypes, with seven (41%) deaths attributed to the most common PFGE subtype. No other subtype accounted for more than two 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, 2004