Group B streptococcus is a common bacterium that is usually carried in the intestines or lower genital tract. The condition is usually harmless in adults. However, in newborns and infants it may cause a serious illness called group B strep disease.

Group B strep can also cause infections in adults who suffer from certain chronic medical conditions such as diabetes or liver disease. Healthy adults may not require treatment for group B strep. A positive group B strep during pregnancy may require antibiotic treatment during labor to protect the baby.





In infants, group B strep can cause illness that can take two forms: early onset or late onset.


Early onset group B strep disease:


  • Fever
  • Difficulty feeding
  • Lethargy


Late onset group B strep disease:


  • Difficulty breathing
  • Fever
  • Difficulty feeding
  • Lethargy
  • Irritability



Adults may be carriers of group B strep but have no signs or symptoms. In some cases, group B strep may cause a urinary tract infection or more serious infection such as blood infections (bacteremia) or pneumonia.



Group B strep bacteria are not sexually transmitted and they are not spread through food or water. Adults may carry the bacteria in the body for a short period, it may come and go or one may always have it.

Group B strep can spread to a newborn baby during delivery or if the baby is exposed to or swallows fluids that contain group B strep.

Older adults and those with chronic health conditions may develop a more serious infection from group B strep.


Risk factors

Risk factors for infants include:


  • A mother that carries group B strep
  • Premature birth (earlier than 37 weeks)
  • The mother’s water breaks 18 hours or more before delivery
  • The mother has an infection of the placental tissues and amniotic fluid (chorioamnionitis)
  • Group B strep bacteria discovered in the mother’s urine during pregnancy
  • The mother’s temperature is greater than 38C during labor
  • The mother previously delivered an infant with group B strep disease


Risk factors for adults include:


  • A medical condition that impairs the immune system such as diabetes, HIV, cancer or liver disease
  • Older than 65



Complications in infants may include:


  • Inflammation of the lungs (pneumonia)
  • Inflammation of the membranes and fluid surrounding the brain and spinal cord (meningitis)
  • Infection in the bloodstream (bacteremia)


Complications during pregnancy may include:


  • Urinary tract infection
  • Infection of the placenta and amniotic fluid (chorioamnionitis)
  • Inflammation and infection of the membrane lining the uterus (endometritis)
  • Infection of the bloodstream (sepsis)


Complications in older adults or people with other chronic health conditions may include:


  • Skin infection (cellulitis)
  • Infection of the bloodstream (sepsis)
  • Urinary tract infection
  • Inflammation of the lungs (pneumonia)
  • Bone and joint infections
  • Infection of the heart valves (endocarditis)
  • Meningitis



If the individual is pregnant, IV antibiotics may be administered to prevent group B strep from spreading to the baby during labor.

Furthermore, researchers are working on a group B strep vaccine that could help prevent group B strep infections in adults.