Group B Strep in Adults & Babies: Risks & Prevention Strategies

What is Group B Strep?

Group B Streptococcus (GBS), or Streptococcus agalactiae, is a naturally occurring bacterium often found in the digestive tract, urinary tract, and vagina. In most healthy adults, this bacterium remains harmless, coexisting as part of the body’s normal bacterial flora. However, under certain conditions, especially during pregnancy or in people with weakened immune systems, GBS can cause serious infections.

In pregnant women, the bacterium may pass from the mother’s birth canal to the baby during delivery. For newborns, this can result in severe complications such as pneumonia, meningitis, or sepsis, which can develop within hours or days after birth. Fortunately, with timely screening and appropriate antibiotic treatment during labour, these risks can be significantly reduced.

GBS infection is not a sexually transmitted disease and cannot be spread through casual contact. It mainly poses risks through direct transmission from mother to child or through infections in immunocompromised individuals.

Global Prevalence & Burden

Globally, Group B Strep colonises an average of 18% of pregnant women, according to the World Health Organisation (WHO). Globally, GBS causes an estimated 320,000 neonatal infections each year, resulting in about 90,000 infant deaths and 46,000 stillbirths.

In India and South Asia, where universal screening is not yet mandatory, studies reveal a maternal colonisation rate ranging between 7% and 20%, highlighting the pressing need for routine antenatal GBS testing. Infants infected with GBS are at higher risk of life-threatening conditions, long-term neurological damage, or developmental delays.

GBS-related infections also contribute significantly to maternal sepsis cases in developing regions, emphasising the need for early diagnosis and treatment as part of comprehensive maternal healthcare.

How Group B Strep Spreads & Colonises

The spread of Group B Strep typically occurs through colonisation rather than contagious spread between people.

Here’s how it happens:

• Natural colonisation: GBS is commonly present in the vagina, rectum, and intestines without causing symptoms.
• Mother-to-child transmission: The primary mode of infection occurs during childbirth, when the baby comes in contact with the bacteria in the birth canal.
• Bloodstream infection: In immunocompromised adults, GBS may enter the bloodstream, causing severe infections such as sepsis.
• Urinary tract infection (UTI): GBS can lead to UTIs in pregnant or elderly adults.
• Wound or surgical site infection: Rarely, it may infect open wounds or post-surgical areas.

GBS is not contagious like influenza or COVID-19, but preventive hygiene and early screening are essential in stopping its spread to newborns.

Risks & Impacts in Babies

In newborns, Group B Strep infection can manifest in two forms:

• Early-Onset Disease (EOD): Occurs within the first 6 days of life. Babies may develop sepsis, pneumonia, or meningitis, often showing symptoms like fever, difficulty breathing, or poor feeding soon after birth.
• Late-Onset Disease (LOD): Typically occurs between 7 and 89 days after birth, usually through environmental exposure or contact with colonised individuals. This form often causes seizures, irritability, or sleepiness.

Untreated GBS infections may lead to neurological injury, hearing loss, or developmental disorders such as cerebral palsy. Early detection and prompt antibiotic treatment are therefore critical in protecting newborn health.

Risks & Impacts in Adults

While GBS is most commonly associated with neonatal infections, adults, especially those with chronic illnesses, can also develop complications, including:

• Urinary tract infections (UTIs): Frequent in older adults or pregnant women.
• Bloodstream infections (Sepsis): Potentially life-threatening in people with diabetes, liver disease, or weakened immunity.
• Bone and joint infections: Such as osteomyelitis or septic arthritis.
• Skin and soft tissue infections: Particularly in surgical wounds or ulcers.
• Pneumonia or meningitis: Rare but severe in immunocompromised adults.

In severe cases, untreated infections can progress to sepsis, potentially leading to multi-organ failure or death, especially in older adults.

Diagnosis & Clinical Management

Accurate diagnosis is crucial for timely treatment and prevention of transmission. Common diagnostic procedures include:

• Vaginal and Rectal Swab Test: Recommended between 35–37 weeks of pregnancy to detect GBS colonisation.
• Urine Culture: Identifies GBS-related urinary infections, particularly in pregnant women.
• Blood Culture: Used in adults or infants showing symptoms of sepsis or meningitis.
• Cerebrospinal Fluid (CSF) Analysis: Performed if meningitis is suspected.

Once detected, the standard treatment involves intrapartum antibiotic prophylaxis (IAP), administered during labour to prevent newborn infection. Penicillin is the preferred antibiotic; however, ampicillin or cefazolin may be used if the patient has a mild allergy. For those with severe penicillin allergy, clindamycin or vancomycin may be considered.

Examinations and Tests to Diagnose Group B Strep

Various tests are employed to diagnose GBS colonisation or infection:

• Group B Streptococcus Culture Test (Vaginal/Rectal Swab) – Detects bacterial presence and helps in antibiotic sensitivity testing.
• Urine Culture Test – Confirms bacterial growth and identifies the infection source.
• Blood Culture Test – Tests like Biofire Blood Panel detects bloodstream infections and sepsis.

Prevention Strategies & Best Practices

Preventing Group B Strep infections involves proactive care and awareness:

• Routine antenatal screening between 35–37 weeks of pregnancy.
• Antibiotic treatment during labour for GBS-positive mothers.
• Maintaining good hygiene, especially handwashing before handling newborns.
• Monitoring newborns closely for early signs of infection after delivery.
• Educating healthcare workers and families about GBS awareness and prevention.

These simple but critical steps can drastically reduce neonatal and maternal complications linked to Group B Strep.

Regional & Practical Considerations (India/South Asia/LMICs)

In low- and middle-income countries like India, several gaps persist in GBS prevention:

• Limited routine screening during antenatal care visits.
• Inconsistent access to antibiotics in rural healthcare centres.
• Lack of awareness among expectant mothers about GBS testing and its importance.

To overcome these challenges, healthcare authorities are now encouraging the integration of GBS screening into standard maternal health programmes. The Indian Council of Medical Research (ICMR) has also recommended greater surveillance of neonatal sepsis to monitor antibiotic resistance trends and improve outcomes for mothers and infants.

Improving public health education, strengthening healthcare provider training, and expanding access to diagnostic services can collectively help reduce the GBS disease burden across India and South Asia.

Summary & Key Takeaways

1. Group B Strep (GBS) is a common bacterium that can cause severe infections in newborns, pregnant women, and vulnerable adults.
2. GBS remains the leading cause of neonatal sepsis and meningitis, associated with significant risks of death and long-term disability.
3. Between 10% and 30% of pregnant women carry GBS, but screening and proper management can significantly reduce the risk to babies.
4. Screening at 35-37 weeks of pregnancy and administration of antibiotics during labour are the best prevention strategies where resources allow.
5. Diagnosis involves vaginal/rectal swab cultures for expectant mothers and blood or cerebrospinal fluid tests for suspected infections in adults or infants.
6. Developing countries face higher burdens due to limited screening and treatment infrastructure.
7. Promising vaccine research is ongoing and could revolutionise prevention in the near future.
8. Prompt recognition and treatment are crucial for improving outcomes in both babies and adults.

Conclusion

Group B Strep may sound alarming, but with routine antenatal testing, prompt antibiotic care, and awareness, it is highly preventable. Protecting yourself and your baby starts with timely screening and medical guidance.

With Metropolis Healthcare, you can access over 4,000 specialised tests, including urine and blood culture tests, backed by expert pathologists and 10,000+ home collection points.

From home sample collection to fast, accurate reports, Metropolis ensures reliable support for every stage of your health journey—making diagnostics simple, accessible, and trustworthy.

FAQs

What is Group B Strep in adults and babies?

It’s a bacterial infection caused by Streptococcus agalactiae that can affect healthy adults, pregnant women, and newborns—sometimes leading to severe illness if untreated.

Can a healthy adult be affected by Group B Strep?

Yes, though rare. Adults with conditions like diabetes or weakened immunity can develop urinary or bloodstream infections.

How is Group B Strep infection in newborns prevented?

• Screening during pregnancy
• Antibiotic treatment during labour
• Monitoring the baby after birth for early signs of infection

What are the symptoms of GBS infection in babies?

• Fever or low temperature
• Breathing difficulties
• Irritability or lethargy
• Poor feeding
• Seizures or abnormal movements

Are there side effects of intrapartum antibiotics?

Mild side effects such as nausea or mild rash may occur, but these are temporary and far less severe than the potential infection risk.

When should a mother with GBS be treated with antibiotics?

During active labour or after rupture of membranes, if she tests positive for Group B Strep.

Is there a vaccine for Group B Strep?

Currently, there is no approved vaccine, though research and clinical trials are underway.

Can Group B Strep return after treatment?

Yes, colonisation can recur. Regular screening in subsequent pregnancies ensures proper management.

References

• https://www.mayoclinic.org/diseases-conditions/group-b-strep/symptoms-causes/syc-20351729
• https://my.clevelandclinic.org/health/diseases/group-b-strep
• https://www.who.int/news-room/fact-sheets/detail/group-b-streptococcus
• https://www.icmr.gov.in
• https://www.who.int/teams/immunization-vaccines-and-biologicals/diseases/group-b-streptococcus-(gbs)