(611) Comparative Effectiveness of Alternate Antibiotic Therapies for Pregnant Patients with Group B Streptococcus Infections

Group B streptococcus infection is the most common cause of early-onset neonatal sepsis. Intrapartum antibiotic therapy is imperative to minimize maternal-to-fetal transmission of Group B Streptococcus (GBS). Penicillin is the agent of choice, with ampicillin or cefazolin as acceptable alternatives, but there is a paucity of data on the efficacy of alternate antibiotic therapies for penicillin-allergic patients. This study evaluates the effectiveness of alternate antibiotic therapies among pregnant patients at an urban safety net hospital.

Study Design:

This was a retrospective analysis of GBS+ pregnant patients from 2019 through 2022. Penicillin-allergic patients were matched 1:2 with non-allergic controls. Primary outcomes were GBS positive neonates, neonatal length of stay, GBS septicemia, Apgar scores, neonatal demise, and 30-day neonatal infectious complications (sepsis, deafness, pneumonia, or meningitis). Chi-square and Fischer exact analyses were performed on Stata version 16.1 (StataCorp, College Station, Texas).

Results:

229 GBS+ pregnant patients were analyzed, including 84 penicillin-allergic (36.7%) and 145 non-allergic (63.3%). Patients were treated with vancomycin (n=66, 28.8%), clindamycin if susceptibilities were performed on maternal GBS culture (n=10, 4.4 %), cephalosporins (n=6, 2.6%), or penicillin/ampicillin (n=147, 64.2%). Rates of GBS positive infants were low but varied by antibiotic treatment (p< 0.01): penicillin (0%); vancomycin (0%); clindamycin (20%); and cephalosporins(16.7%). There was a significant difference in 30-day neonatal complications (p=0.03): penicillin (2.0%); vancomycin(0%); clindamycin (10%); and cephalosporins(16.7%) but no difference in length of stay, 1 or 5-minute Apgar scores, or neonatal demise.

Conclusion:

Antibiotic effectiveness for GBS+ pregnant patients varied slightly by medication, but risk was low in all cohorts. Vancomycin appears to be most effective in reducing neonatal morbidity among penicillin-allergic patients, but alternative antibiotic therapies may also provide adequate coverage with a lower risk of promoting antibiotic resistance.