Treatment for Group B Strep Urinary Tract Infection in Penicillin-Allergic Patients

Medication Selection Based on Allergy History

The Centers for Disease Control and Prevention recommends cefazolin as the preferred agent for penicillin-allergic patients who do not have a history of anaphylaxis, angioedema, respiratory distress, or urticaria following administration of penicillin or cephalosporin 1, 2
The dosing for cefazolin is 2g IV initial dose, then 1g IV every 8 hours until delivery for pregnant patients, based on pharmacologic data suggesting cefazolin achieves effective concentrations 2
For patients with a history of anaphylaxis, angioedema, respiratory distress, or urticaria following penicillin or cephalosporin administration, vancomycin is recommended at 1g IV every 12 hours 1, 2
Clindamycin is also an option at 900mg IV every 8 hours, but only if the isolate is confirmed susceptible 1, 2

The Centers for Disease Control and Prevention recommends susceptibility testing on GBS isolates from penicillin-allergic patients at high risk for anaphylaxis 3, 4
Testing for inducible clindamycin resistance should be performed on isolates that are susceptible to clindamycin but resistant to erythromycin 3, 5
If an isolate is resistant to erythromycin, it might have inducible resistance to clindamycin, even if it appears susceptible 2

GBS in urine at concentrations of ≥10⁴ colony-forming units/ml should be reported and treated 3, 4
Antimicrobial agents should not be used before the intrapartum period to treat GBS colonization in pregnant women, as such treatment is not effective in eliminating carriage or preventing neonatal disease 6, 7

Resistance to clindamycin and erythromycin among GBS isolates has been increasing, necessitating careful antibiotic selection 6