Symptoms and causes

Symptoms

Infants

Most babies born to women carrying group B strep are healthy. But the few who are infected by group B strep during labor can become critically ill.

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

Early-onset group B strep disease. A baby with early-onset group B strep disease becomes sick within one week after birth. Signs and symptoms may include:

  • Fever
  • Difficulty feeding
  • Lethargy

Late-onset group B strep disease. Late-onset group B strep disease develops within a week to a few months after birth, usually within the first month. Signs and symptoms may include:

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

Adults

If you're like many adults, you may carry group B strep in your body, usually in your bowel, vagina, rectum, bladder or throat. Most adults simply carry the bacterium and have no signs or symptoms.

In some cases, group B strep may cause a urinary tract infection or more serious infections such as blood infections (bacteremia) or pneumonia.

When to see a doctor

As an adult, if you experience any signs or symptoms of group B strep infection — particularly if you're pregnant, you have a chronic medical condition or you're older than 65 — contact your doctor right away.

If you notice your infant has any of the signs or symptoms of group B strep disease, tell your baby's doctor immediately.

Causes

Many healthy people carry group B strep bacteria in their bodies. Group B strep bacteria aren't sexually transmitted, and they're not spread through food or water. You may carry group B strep in your body for just a short period of time, it may come and go, or you may always have it.

Group B strep can spread to a baby during a vaginal delivery if the baby is exposed to — or swallows — fluids containing group B strep.

Some individuals, such as older adults and those with chronic health conditions, can develop a more serious infection from group B strep. However, the reason this occurs in some people but not others isn't known.

Risk factors

Infants

An infant is at increased risk of developing group B strep disease if:

  • The mother carries group B strep in her body
  • The baby is born prematurely (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 have been detected in the mother's urine (bacteriuria) during pregnancy (either her current pregnancy or previous pregnancies)
  • The mother's temperature is greater than 100.4 F (38 C) during labor
  • The mother previously delivered an infant with group B strep disease

Adults

You're at increased risk of a group B strep infection if:

  • You have a medical condition that impairs your immune system, such as diabetes, HIV infection, cancer or liver disease
  • You're older than 65, particularly if you live in a nursing home

Complications

Group B strep infection can lead to life-threatening complications in infants, including:

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

If you're a pregnant woman, group B strep can cause:

  • 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)

If you're an older adult or you have a chronic health condition, group B strep bacteria may cause complications such as:

  • 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)
  • Inflammation of the membranes and fluid surrounding the brain and spinal cord (meningitis)
April 26, 2016
References
  1. Puopolo KM, et al. Group B streptococcal infection in neonates and young infants. http://www.uptodate.com/home. Accessed Feb. 22, 2016.
  2. Group B strep. Centers for Disease Control and Prevention. http://www.cdc.gov/groupbstrep/about/index.html. Accessed Feb. 22, 2016.
  3. Hay WW, et al. The newborn infant. In: Current Diagnosis & Treatment: Pediatrics. 22nd ed. New York, N.Y.: McGraw-Hill Education; 2014. http://www.accessmedicine.com. Accessed Feb. 22, 2016.
  4. Barshak M, et al. Group B streptococcal infections in nonpregnant adults. http://www.uptodate.com/home. Accessed Feb. 22, 2016.
  5. Puopolo KM, et al. Group B streptococcal infection in pregnant women. http://www.uptodate.com/home. Accessed Feb. 22, 2016.