Group B streptococcus infection

Group B Streptococcus Infection

Group B Streptococcus (GBS) infection is a bacterial infection caused by the bacterium *Streptococcus agalactiae*. It is a significant cause of illness in newborns, pregnant women, and adults with certain chronic medical conditions. GBS is part of the normal flora of the gastrointestinal and genitourinary tracts in some individuals, but it can become pathogenic under certain circumstances.

Epidemiology

GBS is commonly found in the gastrointestinal and genital tracts of healthy adults. It is estimated that 10-30% of pregnant women are colonized with GBS. The bacterium can be transmitted from mother to child during childbirth, leading to neonatal infections.

Pathophysiology

GBS can cause a range of infections, including:

• Neonatal infections: These can be early-onset (within the first week of life) or late-onset (after the first week). Early-onset disease is typically acquired during delivery and can lead to sepsis, pneumonia, and meningitis.
• Infections in pregnant women: GBS can cause urinary tract infections, chorioamnionitis, and postpartum infections.
• Infections in adults: In adults with chronic medical conditions, GBS can cause skin and soft tissue infections, bacteremia, and pneumonia.

Clinical Manifestations

Neonatal Infections

• Early-onset disease: Symptoms include respiratory distress, apnea, lethargy, and temperature instability. It can rapidly progress to sepsis and meningitis.
• Late-onset disease: Symptoms may include fever, irritability, poor feeding, and seizures.

Infections in Pregnant Women

• Symptoms of urinary tract infections include dysuria, frequency, and urgency.
• Chorioamnionitis may present with fever, uterine tenderness, and fetal tachycardia.

Infections in Adults

• Symptoms vary depending on the site of infection but may include fever, chills, and localized pain or swelling.

Diagnosis

Diagnosis of GBS infection is typically made by isolating the bacterium from a sterile site, such as blood or cerebrospinal fluid. In pregnant women, screening for GBS colonization is recommended between 35 and 37 weeks of gestation using a vaginal and rectal swab.

Prevention

Intrapartum antibiotic prophylaxis (IAP) is the primary strategy for preventing early-onset GBS disease in newborns. Pregnant women who are colonized with GBS or have risk factors for transmission are given antibiotics during labor to reduce the risk of neonatal infection.

Treatment

GBS infections are treated with antibiotics. Penicillin is the antibiotic of choice, but alternatives such as ampicillin or cefazolin may be used in patients with penicillin allergies.

Also see

• Streptococcus agalactiae
• Neonatal sepsis
• Bacterial meningitis
• Intrapartum antibiotic prophylaxis