Streptococcal Invasive Disease - Group A, 2001
Two hundred cases of invasive group A streptococcal (GAS) disease (4.1 per 100,000 population), including 15 deaths, were reported in 2001, compared to 149 cases and 13 deaths in 2000. Ages of case-patients ranged from 1 month to 97 years (mean, 47 years). Fifty-nine percent of case-patients were residents of the seven-county Twin Cities metropolitan area. Thirty-seven (19%) cases had bacteremia without another focus of infection, 47 (24%) had cellulitis, and 16 (8%) had primary pneumonia. Seventeen (9%) cases had necrotizing fasciitis. Six (3%) cases had streptococcal toxic shock syndrome (STSS); three STSS cases also had necrotizing fasciitis, and two others had peritonitis.
Of the 15 deaths, four (27%) had bacteremia without another focus of
infection, and four had necrotizing fasciitis, including one patient who
also had STSS and one who also had pneumonia. The remaining fatal cases
had bacteremia with another focus of infection, including two (13%) with
pneumonia, two (18%) with cellulitis, and one (7%) each with necrotizing
fasciitis and septic arthritis. The deaths occurred in persons 35 to 91
years of age. Significant underlying medical conditions were reported
for all but three of the deaths.
Isolates were available for 174 (87%) cases, of which 166 were subtyped using pulsed-field gel electrophoresis (PFGE). Fifty-three different molecular subtypes were identified. Thirty-two subtype patterns were represented by one isolate each; other subtypes were represented by two to 38 isolates each. No epidemiologic links were noted among cases with identical subtypes, except for one pair of cases from the same nursing home. The deaths were distributed among eight different subtypes, with five (33%) deaths attributed to the most common PFGE subtype (5/38 [13%] of cases with that subtype). No other subtype accounted for more than two deaths.