Invasive group A streptococcal infections in Florida.

Background: Several previous studies of invasive Group A streptococcal (GAS) disease have been hindered by small sample sizes (≤ 100 patients) and limited generalizability. Methods: We conducted a population-based study of invasive GAS disease. The objectives of the study were to describe the clinical features of individuals who were hospitalized for invasive GAS disease and to identify risk factors for hospital mortality. The cases were 257 patients who were hospitalized throughout Florida during a 4-year period and reported to the Florida Department of Health. Logistic regression was used to calculate adjusted odds ratios (OR) for mortality and 95% confidence intervals (CI). Results: The overall mortality was 18% (41 of 228). Admission into an intensive care unit was a strong predictor of mortality (OR, 20.41; 95% CI, 6.41-64.96). Treatment with clindamycin reduced mortality in patients who had necrotizing fasciitis (OR, 0.11; 95% Cl, 0.01-0.89) but not in patients who did not have necrotizing fasciitis (OR, 1.01; 95% CI, 0.31-3.33). Conclusion: Clindamycin reduces mortality in patients with invasive GAS disease who have necrotizing fasciitis.