From the Guidelines
The most appropriate pharmacotherapy for this patient is intravenous vancomycin. Given her positive Group B Streptococcus (GBS) culture at 36 weeks gestation and her history of penicillin allergy (manifested as a maculopapular rash), vancomycin is the recommended antibiotic for intrapartum GBS prophylaxis, as suggested by the guidelines from 1. The standard dosing is 1 g intravenously every 12 hours until delivery. Since her GBS culture showed resistance to erythromycin, which is often used as an alternative in penicillin-allergic patients, vancomycin becomes the preferred choice. Clindamycin could be considered if the GBS isolate was known to be susceptible, but given the documented erythromycin resistance, vancomycin is more appropriate as cross-resistance between erythromycin and clindamycin is common, as noted in 1 and 1.
Key Considerations
- The patient's penicillin allergy, although manifested as a nonpruritic maculopapular rash, necessitates caution and the use of alternative antibiotics for GBS prophylaxis.
- The resistance of the GBS isolate to erythromycin increases the likelihood of cross-resistance to clindamycin, making vancomycin a safer choice.
- Intrapartum antibiotic prophylaxis is crucial to prevent early-onset GBS disease in the newborn, which can cause serious complications including sepsis, pneumonia, and meningitis, as highlighted in 1.
- The first dose of vancomycin should be administered at the start of induction and continued until delivery to ensure adequate protection for the newborn.
Rationale for Vancomycin
The choice of vancomycin over other options like clindamycin is based on the erythromycin resistance of the GBS isolate and the patient's penicillin allergy. While clindamycin could be an option if the GBS isolate is susceptible, the presence of erythromycin resistance complicates this choice due to potential cross-resistance, as discussed in 1. Vancomycin, therefore, offers a more reliable and safer alternative for preventing early-onset GBS disease in the newborn. This approach aligns with the most recent guidelines for the management of GBS disease, as outlined in 1.
From the FDA Drug Label
Erythromycin is effective in eliminating the organism from the nasopharynx of infected individuals, rendering them noninfectious Some clinical studies suggest that erythromycin may be helpful in the prophylaxis of pertussis in exposed susceptible individuals. Primary syphilis caused by Treponema pallidum. Erythromycin (oral forms only) is an alternative choice of treatment for primary syphilis in patients allergic to the penicillins. Prevention of Initial Attacks of Rheumatic Fever Penicillin is considered by the American Heart Association to be the drug of choice in the prevention of initial attacks of rheumatic fever (treatment of Streptococcus pyogenes infections of the upper respiratory tract e.g., tonsillitis, or pharyngitis). Erythromycin tablets are indicated for the treatment of penicillin-allergic patients.
The patient has a penicillin allergy and is positive for group B Streptococcus (GBS). However, the provided drug label does not directly address the treatment of GBS in pregnant women with a penicillin allergy. Given the patient's penicillin allergy and the need for an alternative treatment, the most appropriate pharmacotherapy would be an antibiotic that is effective against GBS and safe for use in pregnant women. However, the label for erythromycin 2 indicates that the patient's GBS is resistant to erythromycin, making it an ineffective treatment option. Since the label does not provide a suitable alternative for GBS treatment in penicillin-allergic patients, and considering the patient's specific condition, no conclusion can be drawn from the provided information.
From the Research
Patient's Penicillin Allergy and GBS Prophylaxis
Given the patient's penicillin allergy, the most appropriate pharmacotherapy for GBS prophylaxis must be considered. The patient developed a nonpruritic maculopapular rash after taking penicillin in her 20s, which is a significant factor in determining the best course of action.
Consideration of Antibiotic Options
- Cefazolin and vancomycin are commonly prescribed for intrapartum neonatal sepsis prophylaxis in patients with penicillin allergies, as seen in the study by 3.
- Clindamycin is also an option, but its use is limited due to increasing resistance rates, as reported by 4 and 3.
- Penicillin skin testing can help confirm or rule out a penicillin allergy, and is recommended for patients with a history of penicillin allergy, as stated in the study by 5 and 6.
Recommended Approach
- According to the study by 5, cefazolin or vancomycin can be used as recommended in CDC guidelines for patients with penicillin allergies.
- The study by 6 suggests that evaluation of penicillin allergy before deciding not to use penicillin or other β-lactam antibiotics is an important tool for antimicrobial stewardship.
- In this case, considering the patient's nonpruritic maculopapular rash after taking penicillin, cefazolin or vancomycin would be a suitable option for GBS prophylaxis, as supported by the studies by 4, 3, and 5.