Role of Cefuroxime in GBS Prophylaxis
Cefuroxime has NO role in Group B Streptococcus prophylaxis during labor and should not be used for this indication. The CDC guidelines explicitly recommend penicillin, ampicillin, or cefazolin (a first-generation cephalosporin) as appropriate agents, but cefuroxime (a second-generation cephalosporin) is not included in the recommended regimens 1, 2.
Why Cefuroxime is Not Recommended
Guideline-Based Exclusion
- The 2010 CDC guidelines for prevention of perinatal GBS disease specify only first-generation cephalosporins (specifically cefazolin) as acceptable alternatives for penicillin-allergic patients without high-risk features for anaphylaxis 1, 3.
- Cefazolin is the only cephalosporin recommended for GBS prophylaxis, with a dosing regimen of 2 g IV initially, then 1 g IV every 8 hours until delivery 2.
Resistance Concerns with Second-Generation Cephalosporins
- GBS isolates resistant to cefoxitin (another second-generation cephalosporin) have been reported since 1996, raising concerns about the entire class 1, 2.
- While GBS remains universally susceptible to penicillin and first-generation cephalosporins, the resistance profile for second-generation agents is less favorable 1, 4.
Correct Algorithm for GBS Prophylaxis
For Penicillin-Tolerant Patients
- First-line: Penicillin G 5 million units IV initially, then 2.5-3.0 million units IV every 4 hours until delivery 1, 2.
- Acceptable alternative: Ampicillin 2 g IV initially, then 1 g IV every 4 hours until delivery 2.
For Penicillin-Allergic Patients WITHOUT High-Risk Features
- Preferred agent: Cefazolin 2 g IV initially, then 1 g IV every 8 hours until delivery 1, 3, 2.
- High-risk features for anaphylaxis include history of anaphylaxis, angioedema, respiratory distress, or urticaria following penicillin or cephalosporin administration 1, 3.
For Penicillin-Allergic Patients WITH High-Risk Features for Anaphylaxis
- If susceptibility testing shows clindamycin susceptibility: Clindamycin 900 mg IV every 8 hours until delivery 1, 3, 2.
- If susceptibility testing unavailable or shows clindamycin resistance: Vancomycin 1 g IV every 12 hours until delivery 1, 3, 2.
- Susceptibility testing for clindamycin and erythromycin must be performed on GBS isolates from high-risk penicillin-allergic patients 1, 2.
Critical Clinical Pitfalls
Cross-Reactivity Considerations
- Approximately 10% of patients with true penicillin allergy have cross-reactivity to cephalosporins, but this risk applies primarily to first-generation agents like cefazolin 2.
- The cross-reactivity risk with second-generation cephalosporins like cefuroxime has not been adequately studied in the GBS prophylaxis context, which is another reason it is not recommended 1.
Resistance Patterns
- Clindamycin and erythromycin resistance rates among GBS isolates range from 13-32%, making susceptibility testing essential before using these agents 1, 5.
- The rate of co-resistance between erythromycin and clindamycin is approximately 92%, meaning erythromycin-resistant isolates are almost always clindamycin-resistant as well 5.
Common Errors in Practice
- Studies show that over 55% of penicillin-allergic women without anaphylaxis receive inappropriate antibiotics (clindamycin or vancomycin) instead of the recommended cefazolin, representing poor adherence to guidelines 6.
- Never use cefuroxime, cefoxitin, or other second-generation cephalosporins for GBS prophylaxis, as they are not validated for this indication and may have inferior efficacy 1, 2.