Streptococcal Invasive Disease - Group B, 2003

Three-hundred and twenty-nine cases of group B streptococcal invasive disease (6.5 per 100,000 population), including 27 deaths, were reported in 2003. These cases were those in which group B Streptococcus (GBS) was isolated from a normally sterile site; three cases of miscarriage or stillbirth in which GBS was cultured from the placenta were also reported.

Overall, 154 (47%) cases presented with bacteremia without another focus of infection. The other most common types of infection were cellulitis (12%), arthritis (7%), osteomyelitis (8%), pneumonia (6%), and meningitis (3%). The majority (74%) of cases had GBS isolated from blood only. Fifty-three percent of cases occurred among residents of the Twin Cities metropolitan area. Thirty-eight (12%) case patients were infants less than 1 year of age, and 178 (54%) were 60 years of age or older.

In 2003 there were 40 cases of infant (early-onset or late-onset) or maternal GBS disease were reported, compared to 59 cases in 2001. Twenty infants developed invasive disease within 6 days following birth (i.e., early-onset disease), and 16 infants became ill at 7 to 89 days of age (i.e., late-onset disease). Three stillbirths or spontaneous abortions were associated with four maternal invasive GBS infections.

From 1997 to 2003, there were 189 early-onset disease cases reported and eight infants died. Thirty-four infants were born at less than 37 weeks’ gestation and accounted for 18% of early-onset cases. Bacteremia without another focus of infection (85%) was the most common type of infection in these early-onset cases, followed by pneumonia (19%) and meningitis (8%).

In August 2002, CDC published revised guidelines for the prevention of perinatal GBS 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 20 early-onset cases reported during 2003. Overall, 13 (68%) of 20 women who delivered GBS-positive infants were screened prenatally for GBS. Of these, 2 (15%) women were positive and 11 (85%) women were negative. Among the seven women who were not prenatally screened for GBS, 1 (14%) was screened upon admission to the hospital and prior to delivery of her infant. Among the 20 women of infants with invasive GBS disease, 6 (30%) received intrapartum antimicrobial prophylaxis (IAP). One of the two 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 IAP use of 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, 2003