Beta Hemolytic Streptococcus Group B

• Group B Strep (GBS) is a common bacterium found in the digestive and lower genital tracts of many healthy individuals.
• Most adults carrying GBS experience no symptoms, but it can cause serious infections in newborns and adults with underlying health conditions.
• Routine screening for GBS is recommended for all pregnant women between 36 and 37 weeks of gestation.
• Intravenous antibiotics administered during labor are the primary method to prevent GBS transmission from mother to baby.
• GBS is not a sexually transmitted infection and cannot be prevented through hygiene alone.

What is Beta Hemolytic Streptococcus Group B (GBS)?

Beta Hemolytic Streptococcus Group B (GBS) is a type of bacteria, specifically Streptococcus agalactiae, commonly found in the intestines and lower genital tract. It is estimated that about one in four pregnant women carry GBS, making it a prevalent bacterium. It is important to note that carrying GBS is not considered an infection in healthy adults and typically does not cause symptoms or require treatment outside of pregnancy. GBS is distinct from Group A Strep, which is responsible for conditions like strep throat.

While GBS carriage is usually asymptomatic, it can sometimes lead to infections in adults, such as urinary tract infections (UTIs), skin or soft tissue infections, pneumonia, and, less commonly, more severe conditions like sepsis or meningitis, especially in older adults or those with chronic health issues like diabetes or liver disease. However, the primary concern surrounding GBS is its potential impact on newborns.

Symptoms and Pregnancy Risks of Group B Strep

For most adults, including pregnant women, carrying GBS does not cause any noticeable symptoms. However, if an infection develops, group b strep symptoms and causes can vary. In adults, GBS can cause UTIs, presenting with symptoms like painful urination, frequent urges to urinate, or lower abdominal pain. More severe infections might manifest as fever, chills, body aches, or localized pain and swelling if it affects skin or soft tissues. The primary cause of these infections is the overgrowth or spread of the naturally occurring GBS bacteria within the body.

The most significant concern regarding GBS is its impact during pregnancy. Group b strep in pregnancy risks primarily involve the potential for transmission to the newborn during vaginal birth. Approximately 1 to 2 out of every 100 babies born to mothers who carry GBS and do not receive preventive antibiotics will develop GBS disease. This can lead to serious, life-threatening conditions in infants, including:

• Early-onset GBS disease: Occurs within the first week of life, often presenting as sepsis (blood infection), pneumonia (lung infection), or meningitis (infection of the fluid and lining around the brain and spinal cord). Symptoms can include fever, difficulty feeding, lethargy, or breathing problems.
• Late-onset GBS disease: Develops weeks or even months after birth, most commonly as meningitis.

For pregnant women, GBS can also increase the risk of complications such as chorioamnionitis (infection of the amniotic fluid and membranes) or postpartum infections, particularly if they develop a fever during labor.

Preventing Group B Strep Infection

The main strategy for how to prevent group b strep infection in newborns involves screening pregnant women and administering antibiotics during labor. The Centers for Disease Control and Prevention (CDC) recommends that all pregnant women be screened for GBS carriage between 36 and 37 weeks of pregnancy. This involves a simple swab of the vagina and rectum, which is then sent to a lab for culture. If the test is positive, it means the woman is a GBS carrier.

If a pregnant woman tests positive for GBS, or if she had GBS in her urine during pregnancy, previously had a baby with GBS disease, or has an unknown GBS status with risk factors (such as fever during labor or prolonged rupture of membranes), she will be offered intravenous antibiotics during labor. Penicillin or ampicillin are typically used and are highly effective in preventing GBS transmission to the baby. Administering antibiotics during labor significantly reduces the risk of early-onset GBS disease in newborns, with studies showing a reduction of up to 80% or more, according to the CDC. It is important to note that antibiotics are not given before labor because the bacteria can regrow quickly, rendering earlier treatment ineffective for preventing transmission during birth.