Group B Streptococcus

(Streptococcus agalactiae)

Group B Streptococcus (GBS), also known as Streptococcus agalactiae, is a major cause of post-partum infection and is also the most common cause of newborn sepsis and meningitis.  Asymptomatic carriage of the bacterium, especially in the gastrointestinal and vaginal tract of women, is common.   Infected newborns typically come in contact with GBS in utero or during birth. The administration of antibiotics at the start of labor, however, reduces the number of GBS present at birth, thereby decreasing the chance of the newborn infection. 

Neonatal GBS disease is categorized as either early-onset or late-onset disease. Early-onset infection presents between 0-6 days of life.  Late-onset is defined as GBS disease acquired at 7 days-old to 3 months of age.  Due to the bacteria’s potential to cause serious, life-threatening illness in infants, it is important for pregnant women to be tested for GBS before delivery.  Knowledge of a woman’s GBS status before giving birth can prevent infection.

Although it is a pathogen more commonly associated with pregnant women and newborns, GBS has also emerged as a cause of illness in adults.  While the mode of transmission in non-pregnant adults is unknown, the elderly and adults with chronic diseases, like diabetes or liver failure, seem to be more susceptible to GBS infection. 

For more information on both Neonatal and Adult GBS infection, please visit the CDC GBS Prevention Site.

Image courtesy of CDC Public Health Image Library

Maryland Emerging Infections Program/ABCs
Johns Hopkins University Bloomberg School of Public Health
Candler Building
111 Market Place, Suite 850, Room 8546
Baltimore, MD 21202
Phone: 410-223-1810
Fax:  410-223-1815
Email: mdabcs@jhsph.edu