Streptococcal Invasive Disease - Group A, 2000
One hundred forty-nine cases (3.0 per 100,000 population) of invasive group A streptococcal (GAS) disease (including 13 deaths) were reported in 2000, compared to 180 cases and 19 deaths in 1999.
Ages of cases ranged from 1 day to 94 years, with a mean of 46 years. Sixty-four percent of cases were residents of the seven-county Twin Cities metropolitan area. Thirty-two (21%) cases had bacteremia without another focus of infection; 44 (30%) had cellulitis, and 18 (12%) had primary pneumonia. Thirteen (9%) cases had necrotizing fasciitis. Nine (6%) cases had streptococcal toxic shock syndrome (STSS); two of the STSS patients had necrotizing fasciitis; one had pneumonia; one had cellulitis, and the remaining five did not have other associated foci of infection.
Of the 13 deaths, five (38%) had STSS, three (23%) had bacteremia without another focus of infection, and one (8%) had meningitis. The remaining cases had bacteremia with another focus of infection, including two (15%) with pneumonia, one (8%) with cellulitis, and one (8%) with an abscess.
Isolates for 120 (81%) cases were available at MDH. Fifty-three different molecular subtypes were identified by pulsed-field gel electrophoresis (PFGE). Thirty-seven (70%) subtype patterns were represented by one isolate each; other subtypes were represented by two to 28 isolates each. No epidemiologic linkages were noted between cases with identical subtypes, except for two pairs of cases from two nursing homes and a pair of extended family members (child and grandparent) living in different households. The deaths were distributed among six different subtypes, with no PFGE subtype accounting for more than two deaths. Isolates were unavailable for four of the patients who died.