A Population-Based Assessment of Invasive Disease Due to Group B Streptococcus in Nonpregnant Adults

TLDR

Group B streptococci are a major cause of meningitis and septicemia in neonates and pregnant women, yet their impact on nonpregnant adults—particularly the elderly and those with chronic diseases—remains poorly defined. The study prospectively surveilled invasive group B streptococcal disease in nonpregnant adults across 35 hospitals in metropolitan Atlanta over 24 months. The authors reviewed clinical and laboratory records of all nonpregnant adults with invasive group B streptococcal disease identified during the surveillance, encompassing 424 cases with an annual incidence of 9.2 per 100,000. Among 424 invasive cases, 48 % were adults (≥18 years) with an annual incidence of 4.4 per 100,000; the most frequent adult diagnoses were skin/soft‑tissue or bone infection (36 %), bacteremia without source (30 %), urosepsis (14 %), pneumonia (9 %), and peritonitis (7 %), with a 21 % mortality rate driven by older age, diabetes, malignancy, and HIV infection.

Abstract

Group B streptococci (Streptococcus agalactiae) are a major cause of meningitis and septicemia in neonates and pregnant women, but the importance of group B streptococcal disease in nonpregnant adults has not been clearly defined.We conducted a prospective surveillance of the pathogens responsible for meningitis for a period of 24 months in 35 hospitals and a referral laboratory in metropolitan Atlanta. We reviewed the clinical and laboratory records of all the nonpregnant adults identified as having invasive group B streptococcal disease during this period.During 1989 and 1990 there were 424 patients with invasive group B streptococcal disease (annual incidence, 9.2 cases per 100,000 population). Of these patients, 46 percent were 1 month of age or younger, 6 percent were older than 1 month but younger than 18 years of age, and 48 percent were 18 or older. Men and nonpregnant women accounted for 68 percent (n = 140) of all cases among adults (annual incidence, 4.4 per 100,000). Clinical and laboratory records were available for 137. In the nonpregnant adult patients (age, 18 to 99 years), the most common clinical diagnoses were skin, soft-tissue, or bone infection (in 36 percent); bacteremia with no identified source (30 percent); urosepsis (14 percent); pneumonia (9 percent); and peritonitis (7 percent). Risk factors included older age (> or = 60 years), the presence of diabetes mellitus, the presence of malignant neoplasms, and infection with the human immunodeficiency virus. The mortality rate in nonpregnant adults was 21 percent, accounting for 67 percent of all deaths related to group B streptococcal infection during the surveillance period.Invasive group B streptococcal infection is a major problem not only in pregnant women and neonates but also in nonpregnant adults, especially those who are elderly and those who have chronic diseases.