Invasive group A streptococcal infections in Sweden in 1994 and 1995: Epidemiology and clinical spectrum

A nationwide study of invasive group A streptococcal (GAS) infections in Sw eden during 1994-1995 was carried out. All Swedish microbiological laborato ries were asked to report isolates of GAS from normally sterile sites. Duri ng the study period they were also asked to send their isolates for T typin g. Questionnaires were sent to the physicians in charge of each patient. Th e incidence, serotype, clinical presentation, symptoms and outcome were rec orded. Clinical data were obtained for 468 of 556 patients with GAS bactera emia, The lethality rate was 16%, but was much higher (37%) in the 113 pati ents who dcl eloped streptococcal toxic shock syndrome (STS). Streptococci of serotype T1 dominated during the study period and were linked to the inc rease in invasive GAS infections. They also carried an increased risk of ca using STSS. Invasive streptococcal disease with STSS most often has an unkn own primary focus or is associated with soft tissue infections. Invasive st reptococcal disease not associated with STSS most often has a skin infectio n as portal of entry or else an unknown focus.