Streptococcal Invasive Disease Group B, 2014

Five hundred forty-eight cases of invasive group B streptococcal (GBS) disease (10.1 per 100,000 population), including 16 deaths, were reported in 2014. In 2013, 595 cases were reported, the largest number of GBS cases reported since surveillance was initiated in 1995.

Annual incidence was highest among infants <1 year of age (52.4 per 100,000 population) and cases aged 70 years or older (36.9 per 100,000). Seven (44%) of the 16 deaths were among cases age 65 years and older. Fifty-six percent of cases were residents of the metropolitan area. Bacteremia without a focus of infection occurred most frequently (26% of infections), followed by cellulitis (18%), septic arthritis (12%), osteomyelitis (9%), abscess (8%), and meningitis (3%). The majority (68%) of cases had GBS isolated from blood; other isolate sites included joint fluid (13%) and bone (6%).

Forty-eight cases were infants or pregnant women (maternal cases), compared to 29 cases in 2013. Sixteen 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 of age [0.2 cases per 1,000 live births]). Twelve stillbirth/spontaneous abortions were associated with the 15 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 2013. Overall, 12 of 16 women who delivered GBS-positive infants underwent prenatal screening for GBS. Of these, 3 were positive, and 9 negative. Two of the four women who did not receive prenatal screening were screened upon admission to the hospital and prior to delivery. Among the 16 women who delivered GBS-positive infants, 7 received intrapartum antimicrobial prophylaxis (IAP). Both of the women with a positive GBS screen after hospital admission received IAP.

• For up to date information see: Group B Streptococcus (GBS)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2014