Population-based study of invasive disease due to β-Hemolytic streptococci of groups other than A and B

Abstract

Background. β-Hemolytic streptococci of groups other than A and B( NABS) are increasingly recognized as causes of clinically significant disease, but precise information about this heterogeneous group is lacking. We report the incidence of NABS infection and describe the epidemiologic and clinical characteristics. Methods. Active, population-based surveillance for invasive NABS was performed over a 2-year period in the 8-county metropolitan Atlanta, Georgia, area and the 3-county San Francisco Bay, California, area. Clinical records were reviewed, and available isolates were sent to the Centers for Disease Control and Prevention( Atlanta) for additional microbiologic characterization. Incidences were calculated using year-appropriate US Census Bureau data. Results. A total of 489 cases of invasive NABS infection were identified( 3.2 cases per 100,000 population). The median age of patients was 55 years; 64% of patients were males, and 87% had underlying diseases. The incidence was higher among black persons than white persons( 4.0 vs. 2.5 cases per 100,000 population; P