What is the most appropriate recommendation for a 29-year-old primigravid woman at 36 weeks' gestation with a history of asymptomatic group B Streptococcus (GBS) bacteriuria, previously treated with fosfomycin, and a rash on her chest after taking amoxicillin for bacterial sinusitis?

From the Guidelines

The most appropriate recommendation for this patient is administration of intrapartum penicillin, given her history of asymptomatic group B Streptococcus (GBS) bacteriuria during the current pregnancy, as indicated by the CDC guidelines 1. This patient has a clear indication for intrapartum antibiotic prophylaxis, regardless of subsequent culture results. The standard regimen would be intravenous penicillin G, starting with a 5 million unit loading dose followed by 2.5-3 million units every 4 hours until delivery. The patient's previous rash while on amoxicillin does not appear to be a true allergic reaction since it resolved spontaneously, so penicillin remains the preferred agent, as supported by the guidelines 1. Intrapartum antibiotic prophylaxis is crucial because GBS bacteriuria indicates heavy colonization, which significantly increases the risk of early-onset GBS disease in the newborn, as highlighted in the CDC guidelines 1. This infection can cause serious complications including sepsis, pneumonia, and meningitis. Collecting another rectovaginal culture is unnecessary since the patient already has a clear indication for prophylaxis based on her history of GBS bacteriuria during this pregnancy, and administering antibiotics to the newborn after delivery would be insufficient to prevent early-onset disease. Key considerations for the patient's care include:

• Monitoring for signs of labor and promptly initiating intrapartum antibiotic prophylaxis
• Ensuring the patient's medical history, including the GBS bacteriuria and previous rash, is clearly documented and communicated to the healthcare team
• Providing education on the importance of intrapartum antibiotic prophylaxis in preventing early-onset GBS disease in the newborn.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Patient Background

• The patient is a 29-year-old primigravid woman at 36 weeks' gestation.
• She has a history of asymptomatic group B Streptococcus (GBS) bacteriuria, previously treated with fosfomycin.
• She developed a rash on her chest after taking amoxicillin for bacterial sinusitis.

Group B Streptococcus (GBS) Infection

• GBS is a common commensal in the genitourinary and gastrointestinal tracts and can be detected in the vagina of approximately 20% of women globally 2.
• Invasive GBS infections in neonates can result in sepsis, pneumonia, meningitis, neurodevelopmental impairment, death, and lifelong disability 2.
• A policy of routine screening for GBS rectovaginal colonization in well-resourced countries can trigger the administration of intrapartum antibiotic prophylaxis (IAP) when prenatal testing is positive, which drastically reduces rates of early-onset disease (EOD) 2.

Prediction of Intrapartum Colonization

• The 35- to 37-week GBS rectovaginal culture might be a poor predictor for intrapartum colonization, with a sensitivity of 69% and specificity of 87% 3.
• There was weak agreement between results at 35 to 37 weeks with intrapartum cultures, and 11 patients (3.7%) were GBS positive intrapartum but negative at 35 to 37 weeks 3.

Antibiotic Resistance and Treatment

• Penicillin G remains the mainstay of therapy for GBS infection, although reduced penicillin susceptibility has been observed in select isolates 4.
• Increased frequency of resistance to non-beta-lactam antibiotics, including clindamycin, erythromycin, and fluoroquinolones, has been observed, with some isolates demonstrating resistance to vancomycin 4.
• Multidrug resistance has been reported in GBS from various origins, including urinary tract infection (UTI) isolates, with high rates of resistance to azithromycin, clindamycin, erythromycin, and tetracycline 5.

Considerations for the Patient

• Given the patient's history of asymptomatic GBS bacteriuria and current gestational age, intrapartum antibiotic prophylaxis (IAP) may be recommended to reduce the risk of EOD in the neonate 2.
• The patient's rash after taking amoxicillin may indicate an allergy, and alternative antibiotics may be considered for IAP 4.
• The patient's GBS status and antibiotic resistance profile should be taken into account when selecting an antibiotic for IAP, and consultation with an infectious disease specialist or obstetrician may be necessary to determine the best course of treatment 4, 5.