Bottom line: The incidence of invasive GBS disease is increasing and is associated with advanced age, black race, and diabetes. GBS accounts for about 1.3% of endocarditis cases in the U.S.
Summary: Skoff TH, et al. Increasing burden of invasive group B streptococcal disease in nonpregnant adults, 1990-2007. Clin Infect Dis. 2009 Jul 1;49(1):85-92. doi: 10.1086/599369.
This is a population-based study of group b streptoccus (GBS) disease in non-pregnant adults in selected counties in 10 US states. A case was defined as isolation of GBS from a normally sterile site in a non-pregnant adult age 18 and older who was a resident of the surveillance area. Invasive GBS disease occurred more frequently in patients who are black or who have diabetes.
During 2007, 607 cases of GBS bacteremia without focus were identified. This translated into about 2.8 cases of GBS bacteremia per 100,000 during that year.
Also, age seems to play a role in GBS septicemia as the frequency was 43.2% in patients age 65 and older compared to those of the 18-39 (36.9%) or 40-64 (35.9%) age groups (p=0.017)
Bor DH, et al. Infective Endocarditis in the U.S., 1998–2009: A Nationwide Study. PLoS One. 2013; 8(3): e60033.
A study of 382,153 patients hospitalized with infective endocarditis from 1998 to 2009 in the US, 1.3% were caused by GBS.