From the Guidelines
For a patient with 10,000 to 50,000 cfu/ml of Group B Beta Hemolytic Streptococcus (Strep agalactiae), the recommended treatment is penicillin G, 5 million units IV initial dose, then 2.5–3.0 million units every 4 hrs until delivery, as the organism is susceptible to penicillin and other beta-lactam antibiotics. This recommendation is based on the guidelines from the Centers for Disease Control and Prevention (CDC) for the prevention of perinatal group B streptococcal disease 1. The guidelines emphasize the importance of intrapartum antibiotic prophylaxis for preventing early-onset group B streptococcal disease, especially in patients with a high risk of transmission to the newborn.
Key considerations for treatment include:
- The patient's susceptibility to penicillin and other beta-lactam antibiotics, which makes these agents effective for treatment
- The potential for anaphylaxis or other severe reactions in patients with a history of penicillin allergy, which would necessitate the use of alternative agents such as cefazolin, clindamycin, or vancomycin
- The importance of adequate dosing and duration of treatment to ensure effective eradication of the organism and prevention of complications
In this case, since the patient's Group B Streptococcus is susceptible to penicillin, penicillin G is the recommended treatment, with an initial dose of 5 million units IV followed by 2.5-3.0 million units every 4 hours until delivery 1. This regimen is expected to provide effective coverage against the organism and reduce the risk of transmission to the newborn.
From the Research
Treatment Recommendations
- The recommended treatment for Group B Beta Hemolytic Streptococcus (Strep agalactiae) is penicillin (Penicillin G) and other beta-lactam antibiotics, as they are susceptible to these drugs 2, 3.
- For patients allergic to penicillin, macrolides and lincosamides can be used as alternative treatments 2.
- The treatment duration with penicillin should be 10 days to optimize cure in GABHS infections, although a 5-day regimen is possible with certain antibiotics like cefpodoxime and azithromycin 4.
Antibiotic Susceptibility
- Group B streptococcal isolates are susceptible to beta-lactam antibiotics, including penicillin, and have low resistance rates to ciprofloxacin, ofloxacin, clindamycin, erythromycin, and clarithromycin 3.
- However, resistance to tetracyclines is significant, with 72.4% and 74.5% of group B streptococcal isolates resistant to doxycycline and tetracycline, respectively 3.
- Inducible MLSB resistance to erythromycin and clindamycin has been reported in 23.1% and 10.7% of group B streptococcal isolates, respectively 2.
Treatment Failure
- Penicillin treatment failures can occur, especially in cases where beta-lactamase-producing bacteria are present, and alternative antibiotics like cephalosporins, clindamycin, macrolides, and amoxicillin-clavulanate may be more effective 5, 6.
- Treatment failure can also be due to noncompliance, carrier state, re-infection, bacterial interference, GABHS intracellular internalization, and penicillin tolerance 6.