Streptococcal Invasive Disease - Group B, 2004

Three-hundred forty-one cases of group B streptococcal invasive disease (6.7 per 100,000 population), including 20 deaths, were reported in 2004. These cases were those in which group B Streptococcus (GBS) was isolated from a normally sterile site; 10 cases of miscarriage or stillbirth in which GBS was cultured from the placenta were also reported.

Overall, 158 (46%) cases presented with bacteremia without another focus of infection. The other most common types of infection were cellulitis (14%), pneumonia (9%), osteomyelitis (8%), arthritis (6%), and meningitis (4%). The majority (72%) of cases had GBS isolated from blood only. Fifty-five percent of cases occurred among residents of the Twin Cities metropolitan area. Forty-five (13%) case-patients were infants less than 1 year of age, and 160 (47%) were 60 years of age or older.

Fifty-seven cases of infant (early-onset or late-onset) or maternal GBS disease were reported, compared to 40 cases in 2003. Twenty-six infants developed invasive disease within 6 days following birth (i.e., early-onset disease), and 18 infants became ill at 7 to 89 days of age (i.e., late-onset disease). Ten stillbirths or spontaneous abortions were associated with thirteen maternal invasive GBS infections.

From 1997 to 2004, there were 215 early-onset disease cases reported and 10 infants died. Forty infants were born at less than 37 weeks’ gestation and accounted for 19% of early-onset cases. Bacteremia without another focus of infection (79%) was the most common type of infection in these early-onset cases, followed by pneumonia (13%) and meningitis (6%).

In August 2002, CDC published the Prevention of Perinatal Group B Streptococcal Disease. Key changes include the recommendation for universal prenatal screening of all pregnant women at 35 to 37 weeks’ gestation and updated prophylaxis regimens for women with penicillin allergies. In light of these revised guidelines, MDH reviewed the maternal charts for all 26 early-onset cases reported during 2004. Overall, 18 (69%) of 26 women who delivered GBS-positive infants underwent prenatal screening for GBS. Of these, six (33%) women were positive and 12 (67%) women were negative. Among the eight women who did not receive prenatal screening for GBS, three (38%) were screened upon admission to the hospital and prior to delivery of her infant. Among the 26 women of infants with invasive GBS disease, seven (27%) received intrapartum antimicrobial prophylaxis (IAP). Two of the six women with a positive GBS screening result received IAP. MDH continues to monitor the incidence of GBS disease among infants, screening for GBS among pregnant women, and the use of IAP for GBS-positive pregnant women during labor and delivery.

• For up to date information see: Group B Streptococcus (GBS)
• Full issue>> Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2004