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GBS Notes - NUR 4636

GBS Overview

  • GBS stands for Group B streptococcus, a naturally occurring bacterium.
  • Found in approximately 50\% of healthy adults as part of normal colonization.
  • GBS is a Gram-positive bacterium that colonizes the gastrointestinal and genitourinary tracts.
  • Women who test positive for GBS are considered carriers.
  • Carrier status is transient and does not indicate illness.

GBS in Pregnancy: Transmission Risk and Impact

  • GBS most often is found in the vagina.
  • It can pass from a pregnant woman to her fetus during labor.
  • This transmission is rare without treatment: about \approx 1\% - 2\% of babies are affected when the mother does not receive antibiotics during labor.
  • The chance of a newborn getting sick is much lower when the mother receives treatment during labor.

GBS and the Newborn: Disease Types and Symptoms

  • GBS infection in newborns can be early-onset or late-onset disease.
  • Early-onset disease occurs within 12\text{--}48\text{ hours} after birth and can involve:
    • inflammation of the coverings of the brain or spinal cord (meningitis),
    • infection of the lungs (pneumonia),
    • infection in the blood (sepsis).
  • Late-onset disease occurs within weeks to months and can involve:
    • meningitis,
    • lack of energy,
    • irritability,
    • poor feeding,
    • high fever.

Testing for GBS

  • Screening for GBS is part of routine prenatal care.
  • The test for GBS is called a culture.
  • Timing: testing is done between 36\text{--}38\text{ weeks} of pregnancy.
  • Procedure: a swab is used to take a sample from the vagina.

Positive GBS Result: Management During Labor

  • If GBS is present, most women will receive antibiotics through an intravenous (IV) line once labor has started.
  • The purpose of this treatment is to help protect the fetus from being infected.
  • The best time for treatment is during labor.
  • Penicillin is the antibiotic most often given to prevent early-onset disease in newborns.
  • While intrapartum antibiotics can help prevent early-onset GBS disease, this treatment does not prevent late-onset disease.
  • If GBS status is "unknown", the patient will receive antibiotics during labor.

Unknown GBS Status

  • When GBS status is not known at the onset of labor, standard practice is to administer intrapartum antibiotics to reduce the risk of early-onset GBS disease in the newborn.

Key Takeaways and Practical Implications

  • GBS colonization is common but often asymptomatic in adults; carriage does not imply illness in the carrier.
  • The primary goal of screening and prophylaxis is to reduce Neonatal Early-Onset GBS disease, which can be severe.
  • Timely testing (36–38 weeks) guides intrapartum antibiotic prophylaxis to protect the newborn.
  • Penicillin remains the first-line antibiotic for prophylaxis during labor.
  • Antibiotics during labor are specifically effective for preventing early-onset disease, not late-onset disease.
  • If GBS status is unknown, antibiotics are given during labor as a precaution to protect the newborn.

Connections to Practice and Foundations

  • Emphasizes the importance of routine prenatal screening and proper timing of interventions to prevent neonatal infection.
  • Highlights the difference between colonization (carrier state) and active infection in the newborn.
  • Demonstrates how prophylaxis during a critical window (labor) can reduce risk even when transmission is possible.