Group B Streptococcus (GBS)

""Group B streptococcus (GBS) is a type of bacteria that can cause infection in newborns and adults. The infection rate is much higher in newborns than adults. In newborns, there are two distinct forms of illness: Early-onset and late onset. It is the most common cause of septicaemia (blood infection) and meningitis (brain infection) among newborns.

Image Content Provider: CDC/DPDx - James A. McGregor, MD, University of Colorado Health Sciences Center


Most people who carry GBS don't show any signs or symptoms. If symptoms do occur, they vary based on the type of infection.

  • Infants with early-onset GBS may have lethargy, irritability, low blood pressure, pneumonia (infection of the lungs), septicaemia (blood infection) and abnormal temperature, heart rate and/or breathing rate.
  • Infants infected with late-onset may appear healthy at first. But they then develop symptoms after the first week of life. Symptoms may include fever, difficulty feeding, irritability or lethargy, difficulty breathing, meningitis and a bluish skin tone.
  • Adults with GBS may have septicaemia, pneumonia (lung infection), skin and soft-tissue infections (including surgical wound infections), bone and joint infections and in rare cases, meningitis.

Approximately one third of Canadians carry GBS bacteria in their intestines without knowing it. An estimated 15 to 40 per cent of pregnant women carry it in their vagina. Normally, the presence of GBS will come and go and does not cause any problems or symptoms. However in certain circumstances GBS bacteria can invade the body and cause serious infection.

  • GBS is early-onset when symptoms appear during the first week of life. It occurs when the bacteria is passed from the mother to the baby, most often during labour and birth.
  • GBS is late-onset when symptoms appear from the first week through three months of life. It occurs when the bacteria is passed from the contaminated hands of a caregiver to the baby after birth. If a baby has late-onset GBS and the mother tests positive for GBS, the source of the infection is often unknown.
  • The source of GBS infection is unknown in adults. As GBS is common in the gastrointestinal tract of men and women, this may be a source of infection.

Treatment of GBS infection will vary based on the kind of infection a person has. The most common treatment in newborns and adults is with antibiotics given through an intravenous (IV) line.


Early-onset GBS can be prevented by giving IV antibiotics during labour to women who test positive for the bacteria late in pregnancy.

The sources of infection for both late-onset and adult GBS are unknown. So the best way to prevent is by always practicing good hand hygiene.

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