Streptococcal Invasive Disease Group B, 2018

Five hundred seventy-nine cases of invasive group B streptococcal (GBS) disease (10.4 per 100,000 population), including 28 deaths, were reported in 2018. By age group, annual incidence was highest among infants <1 year of age (44.7 per 100,000 population) and cases aged ≥70 years (39.9 per 100,000). Fifteen (54%) of the 28 deaths were among cases ≥65 years. Fifty-one percent of cases were residents of the metropolitan area. Bacteremia without a focus of infection occurred most frequently (31%), followed by cellulitis (24%), septic arthritis (9%), septic shock (8%), abscess (5%), pneumonia (5%), osteomyelitis (4%), and meningitis (3%). The majority (83%) of cases had GBS isolated from blood; other isolate sites included joint fluid (10%), peritoneal fluid (3%), cerebrospinal fluid (1%), and bone (1%).

Twenty-nine cases were infants and 4 were maternal cases, compared to 42 cases in 2017. Twelve infants developed early-onset disease (occurred within 6 days of birth [0.2 cases per 1,000 live births]), and 17 infants developed late-onset disease (occurred at 7 to 89 days [0.2 cases per 1,000 live births]). Four stillbirth/ spontaneous abortions were associated with the 4 maternal GBS infections.

Since 2002, there has been a recommendation for universal prenatal screening of all pregnant women at 35 to 37 weeks gestation. In light of this, we reviewed the maternal charts for all early-onset cases reported in 2018. Overall, 6 of 12 women who delivered GBS positive infants underwent prenatal screening for GBS. Of these, 1 was positive and 5 were negative. One of the 6 women who did not receive prenatal screening was screened upon admission to the hospital and prior to delivery, and was positive. Among the 12 women who delivered GBS-positive infants, 7 received intrapartum antimicrobial prophylaxis. An update of GBS perinatal prevention guidance was published by the American College of Obstetricians and Gynecologists, and by the American Academy of Pediatrics in July 2019.

• For up to date information see: Group B Streptococcus (GBS)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2018