Condition Basics

What is group B streptococcal infection?

Group B streptococcal (group B strep) infection is a serious bacterial infection that is a leading cause of death and disability in newborns.

In the 1970s, about half of newborns with group B strep infection died. Today, due to early recognition and aggressive treatment of the infection, far fewer cases end in death.

What causes it?

Group B strep bacteria normally exist in the intestine, vagina, or rectum. A pregnant woman can transmit the bacteria to her baby during delivery. Some women are carriers of group B streptococcal bacteria, which means that they carry the bacteria but have no illness from it. It is unclear why some babies get group B strep infection and others do not.

Newborns may develop the infection hours after birth or during the first week of life, or it may happen several months later. Newborns who develop group B strep within the first week are most always infected by their mothers. It's not clear how babies who develop the infection later are exposed to the bacteria.

What are the symptoms?

Symptoms of group B strep may include high or low body temperature, irritability, low energy, raised respiratory rate, and trouble feeding. Newborns infected with group B strep may get a blood infection (sepsis) or lung infection (pneumonia). An infection of the fluid or tissues that surround the brain and spinal cord (meningitis) can also occur. Newborns thought to be infected with group B strep need medical care right away, as the infection can be deadly.

How is it diagnosed?

Pregnant women get tested for group B strep in the third trimester of pregnancy. Babies suspected of being infected are diagnosed at birth by testing their blood or spinal fluid or both for group B strep bacteria.

How is group B streptococcal infection treated?

Pregnant women who have group B strep infection or who are carriers of group B strep will be given antibiotics prior to delivery to prevent transmission of the bacteria to the newborn during delivery. If a woman is pregnant and has previously given birth to a child with group B strep infection or has had tests that show she carries the bacteria, she should be treated with antibiotics.

Newborns with the infection will also be given antibiotics. In addition to antibiotics, supportive care including fluids and ventilation will be given if needed. In some cases, a doctor will treat a newborn that is suspected of having group B strep infection before test results have shown infection. This is because not treating strep B infection in newborns can result in illness or death.

Having a baby by caesarean section does not prevent the transmission of group B strep bacteria.