Group B streptococcal infection

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== Group B Streptococcal Infection ==

Group B streptococcal infection (GBS) is a bacterial infection caused by the bacterium Streptococcus agalactiae. It is a significant cause of neonatal infections, sepsis, pneumonia, and meningitis in newborns. GBS can also cause serious illness in pregnant women, the elderly, and adults with underlying health conditions.

Epidemiology

GBS is commonly found in the gastrointestinal tract and the genitourinary tract of healthy adults. Approximately 10-30% of pregnant women are colonized with GBS in the vagina or rectum. The bacterium can be transmitted to newborns during childbirth, leading to early-onset GBS disease, which occurs within the first week of life, or late-onset GBS disease, which occurs from one week to three months of age.

Pathogenesis

GBS can invade the amniotic fluid and infect the fetus, leading to chorioamnionitis, preterm birth, and stillbirth. In newborns, GBS can cause bacteremia, pneumonia, and meningitis. The bacterium's virulence factors include the capsular polysaccharide, which helps it evade the immune system, and various adhesins that facilitate colonization and invasion of host tissues.

Clinical Manifestations

In newborns, GBS infection can present with symptoms such as respiratory distress, lethargy, poor feeding, and temperature instability. In adults, GBS can cause urinary tract infections, skin and soft tissue infections, bacteremia, and endocarditis.

Diagnosis

GBS infection is diagnosed through culture of the bacterium from sterile body fluids such as blood, cerebrospinal fluid, or urine. Polymerase chain reaction (PCR) and other molecular diagnostic techniques can also be used for rapid detection.

Prevention

Preventive measures include screening pregnant women for GBS colonization at 35-37 weeks of gestation and administering intrapartum antibiotic prophylaxis (IAP) to those who test positive. Penicillin is the antibiotic of choice for IAP, with ampicillin as an alternative.

Treatment

The treatment of GBS infection involves the use of antibiotics. In newborns, empirical therapy often includes ampicillin and gentamicin until GBS is confirmed, after which penicillin or ampicillin is continued. In adults, the choice of antibiotics depends on the site and severity of the infection.

See Also

• Neonatal infection
• Sepsis
• Pneumonia
• Meningitis
• Bacteremia
• Endocarditis
• Urinary tract infection
• Chorioamnionitis
• Preterm birth
• Stillbirth