Spectrum of disease in bacteraemic patients during a Streptococcus pyogenes serotype M-1 epidemic in Norway in 1988.

All 87 known cases of bacteraemia due to Streptococcus pyogenes (beta-haemolytic group A streptococci) occurring during the peak of a nationwide outbreak in Norway (population 4.2 million) between January and June 1988 were reviewed. Clinical features varied widely and appeared largely to be dependent on the patients' age. The case fatality rate ranged from 11% in the age group under 30 years to 44% in patients over 60 years. Clinical complications such as shock, severe renal or respiratory failure or serious local infection occurred particularly in 30-to 59-year old individuals. Shock was manifest in 32% of the patients and carried a 68% case fatality rate. Chronic heart disease in the elderly and pneumonia seemed to be associated with a fatal outcome. In the 25 patients (29%) who died the disease showed a fulminant course, 80% dying within 48 hours after admission. However, 56% of the patients had experienced symptoms for more than two days before admission, suggesting that early diagnosis and treatment might possibly have prevented the development of a serious disease. This study revealed a wide spectrum of clinical manifestations in bacteraemia cases in a unique epidemiological situation caused largely by a single serotype of Streptococcus pyogenes; 89% of the 27 preserved bacteraemia strains carried the M-1 antigen. The observations call attention to the ability of these organisms to cause fulminant clinical illness, indicating a probable increase in both invasiveness and toxicity of group A streptococci responsible for the epidemic.