From the Guidelines
Penicillin G is the first-line antibiotic for treating Streptococcus agalactiae (Group B Streptococcus) infections, with a recommended regimen of 5 million units IV initial dose, then 2.5-3 million units every 4 hours until delivery for intrapartum antibiotic prophylaxis in pregnant women with GBS colonization. The choice of antibiotic is crucial in preventing the transmission of GBS to the newborn and reducing the risk of early-onset GBS disease. According to the most recent guidelines from the CDC 1, penicillin G is the preferred agent for intrapartum antibiotic prophylaxis in women without a penicillin allergy. For patients with penicillin allergies, alternatives include cefazolin, clindamycin, or vancomycin, depending on the severity of the allergy and the susceptibility of the GBS isolate.
Key Considerations
- The CDC recommends penicillin G as the first-line antibiotic for intrapartum antibiotic prophylaxis in pregnant women with GBS colonization 1.
- For patients with penicillin allergies, cefazolin is the preferred agent, but clindamycin or vancomycin may be used depending on the severity of the allergy and the susceptibility of the GBS isolate 1.
- The recommended regimen for penicillin G is 5 million units IV initial dose, then 2.5-3 million units every 4 hours until delivery 1.
- It is essential to complete the full course of antibiotics to ensure complete eradication of the infection.
Treatment Options
- Penicillin G: 5 million units IV initial dose, then 2.5-3 million units every 4 hours until delivery 1.
- Ampicillin: 2 g IV initial dose, then 1 g IV every 4 hours until delivery 1.
- Cefazolin: 2 g IV initial dose, then 1 g IV every 8 hours until delivery 1.
- Clindamycin: 900 mg IV every 8 hours until delivery 1.
- Vancomycin: 1 g IV every 12 hours until delivery 1.
From the FDA Drug Label
Penicillin G is highly active in vitro against streptococci (groups A, B, C, G, H, L, and M) The antibiotic that treats strep agalactiae (also known as group B streptococci) is penicillin G (IV) 2.
From the Research
Antibiotic Treatment for Strep Agalactiae
- The primary antibiotic recommended for treating Strep Agalactiae (Group B streptococcus) is Penicillin G 3, 4, 5.
- For individuals allergic to penicillin, alternative antibiotics such as Erythromycin, Vancomycin, and Clindamycin may be used 3, 6, 4, 7, 5.
- However, resistance to Erythromycin and Clindamycin has been reported, making Vancomycin a more reliable option for penicillin-allergic patients 3, 6, 7, 5.
- Ampicillin and cefazolin are also effective against Strep Agalactiae and may be used as alternatives to penicillin 4, 7, 5.
- It is essential to note that antibiotic susceptibility testing should be performed to determine the most effective treatment for each individual case 3, 7.