Group B Streptococcus, commonly known as Group B Strep or GBS, is a type of bacterial infection that can be found in the digestive and lower reproductive tracts of both men and women. While it is generally harmless in healthy adults, Group B Strep can pose serious health risks to newborns, pregnant women, and individuals with weakened immune systems. It is one of the leading causes of infections in newborns, including sepsis, pneumonia, and meningitis, making awareness, screening, and preventive measures crucial during pregnancy and childbirth. Understanding the causes, symptoms, risk factors, and treatment options for Group B Strep is vital for protecting both maternal and infant health.
Understanding Group B Strep
Group B Streptococcus is a gram-positive bacterium that naturally resides in the human gastrointestinal and urogenital tracts. Approximately 20-30% of pregnant women carry GBS in their vagina or rectum without showing any symptoms. In most cases, this colonization is harmless. However, the bacteria can be transmitted to a baby during labor and delivery, leading to early-onset infections that occur within the first week of life or late-onset infections that appear after the first week and up to several months of age.
Types of Group B Strep Infections
Group B Strep infections can affect both adults and newborns, but the severity and outcomes vary
- Early-Onset GBS in NewbornsOccurs within the first seven days of life and can cause sepsis, pneumonia, and meningitis. Symptoms often appear within hours after birth.
- Late-Onset GBS in NewbornsDevelops after the first week of life and may result in meningitis or bloodstream infections. It can occur even if the mother tested negative for GBS during pregnancy.
- Adult GBS InfectionsIn adults, GBS can cause urinary tract infections, skin infections, bloodstream infections, and rarely, pneumonia. Older adults or those with chronic illnesses such as diabetes or immune deficiencies are at higher risk.
Causes and Transmission of Group B Strep
Group B Strep colonization occurs naturally in the body, and the exact cause of why some people carry the bacteria while others do not is not fully understood. Transmission is particularly concerning during childbirth
Maternal Colonization
Pregnant women may carry GBS in the vagina or rectum without showing symptoms. Colonization can vary over time, so a woman may test negative early in pregnancy but be positive later. Screening is generally performed between 35 and 37 weeks of gestation to identify colonized women.
Transmission to Newborns
During labor and delivery, GBS can pass from the mother to the baby. Risk factors for transmission include
- Premature birth (before 37 weeks of gestation).
- Prolonged rupture of membranes (water breaking more than 18 hours before delivery).
- Maternal fever during labor.
- Previous infant affected by GBS infection.
Symptoms of Group B Strep
Symptoms of GBS infection differ between adults and newborns, and in some cases, colonization may not cause any noticeable signs.
In Newborns
Early-onset GBS infection in newborns may present with
- Respiratory distress or difficulty breathing.
- Fever or low body temperature.
- Lethargy or poor feeding.
- Seizures in severe cases.
Late-onset infection symptoms may include
- Bulging soft spot on the baby’s head (fontanelle) due to meningitis.
- Fever and irritability.
- Poor feeding or vomiting.
- Seizures or other neurological signs.
In Adults
Adults infected with GBS may experience
- Urinary tract infections, causing frequent urination, pain, or blood in the urine.
- Skin and soft tissue infections, leading to redness, swelling, and warmth.
- Bloodstream infections (sepsis), resulting in fever, chills, low blood pressure, and fatigue.
- Rarely, pneumonia or infections of other internal organs.
Screening and Diagnosis
Screening for Group B Strep is an important preventive measure, particularly in pregnant women. The standard screening method involves a swab taken from the vagina and rectum between 35 and 37 weeks of pregnancy. The sample is sent to a laboratory for bacterial culture to determine if GBS is present.
Diagnostic Testing
In addition to routine screening, GBS infections in newborns or adults are diagnosed using blood, urine, or cerebrospinal fluid cultures. Rapid molecular tests may also be used to detect GBS DNA, providing faster results than traditional cultures.
Prevention of Group B Strep Transmission
Preventive strategies focus on reducing the risk of neonatal GBS infection and protecting vulnerable adults
- Intrapartum Antibiotic ProphylaxisPregnant women who test positive for GBS or have risk factors for transmission are given intravenous antibiotics during labor to prevent passing the bacteria to the newborn.
- Good Hygiene PracticesProper handwashing, personal hygiene, and safe handling of medical devices help reduce adult infections.
- Screening and MonitoringRoutine prenatal screening and monitoring of high-risk adults allow for early intervention and treatment.
Treatment of Group B Strep
Group B Strep infections require prompt medical attention. The type of treatment depends on the patient’s age, health status, and severity of the infection.
Treatment in Newborns
Newborns with confirmed GBS infection are treated with intravenous antibiotics, usually penicillin or ampicillin. Early treatment is critical to prevent severe complications such as sepsis or meningitis. Hospitalization is often necessary for close monitoring and supportive care.
Treatment in Adults
Adults with GBS infections are treated with antibiotics tailored to the type and severity of infection. Commonly used antibiotics include penicillin, ampicillin, or vancomycin in cases of resistance. Prompt treatment prevents complications and reduces the risk of bloodstream infections or organ involvement.
Complications of Group B Strep
If left untreated, GBS can lead to serious complications, particularly in newborns. Early-onset infections may cause respiratory failure, sepsis, and death. Late-onset infections can result in meningitis, neurological damage, and long-term developmental delays. In adults, untreated infections may lead to bloodstream infections, organ failure, or severe skin and soft tissue damage.
Group B Strep is a common bacterial colonization that can be harmless in healthy adults but poses significant risks to newborns and certain vulnerable populations. Understanding its causes, transmission, symptoms, screening, prevention, and treatment is essential for maintaining maternal and infant health. Routine prenatal screening, intrapartum antibiotic prophylaxis, and prompt treatment of infections in adults and newborns are key strategies to reduce the risk and complications associated with GBS. Awareness and proactive healthcare measures ensure that both mothers and infants are protected, highlighting the importance of early detection and effective medical intervention.