Streptococcal infections (Group B)

Group B Streptococcus (GBS) are bacteria that commonly live in people’s gastrointestinal and genital tracts. Most of the time the bacteria are not harmful and do not make people sick. GBS bacteria are harmless when they stay where they are supposed to be. However, the bacteria can cause harm when they invade parts of the body where they are not supposed to be, such as in the blood, bones, lungs, or other organs. When GBS bacteria gets into these body parts, it is called invasive GBS disease and can cause bloodstream infections, bone and joint infections, and lung infections that can be deadly.

Newborn babies, pregnant individuals, adults older than 65, and people who have weakened immune systems are most at risk for complications from invasive GBS disease. Invasive GBS disease is the most common cause of life-threatening infections in newborns. Pregnant women can carry GBS and have no symptoms. This is why all pregnant women should be tested for GBS late in pregnancy (36–37 weeks). If you are pregnant and you test positive for GBS, your doctor can provide treatment to make sure your baby does not get infected with GBS when you give birth.

GBS comes and goes naturally in people’s bodies which is why not much is known about how it spreads to others. There are currently no vaccines to prevent invasive GBS disease.