From the FDA Drug Label
Serious infections, such as pneumonia and endocarditis, due to susceptible strains of streptococci (including S (maximum dose of 12 to 20 million units/day) (penicillin-susceptible strains)
The best antibiotic for the treatment of UTI with STREPTOCOCCUS AGALACTIAE (GROUP B) is penicillin G (IV), given its effectiveness against susceptible strains of streptococci, including penicillin-susceptible strains. The recommended dosage is up to 12 to 20 million units/day. 1
From the Research
Penicillin G or ampicillin is the first-line antibiotic treatment for urinary tract infections (UTIs) caused by Group B Streptococcus (Streptococcus agalactiae). For outpatient treatment, amoxicillin 500 mg three times daily for 5-7 days is typically recommended, as supported by the most recent study 2. This recommendation is based on the fact that Group B Streptococcus remains highly susceptible to penicillins, which effectively target the bacterial cell wall synthesis. The following key points should be considered:
- For patients with penicillin allergy, alternatives include cephalexin 500 mg four times daily, or in cases of severe penicillin allergy, clindamycin 300 mg four times daily for 5-7 days, although high resistance to clindamycin has been reported 2, 3.
- For complicated or severe infections, intravenous therapy may be necessary, typically with ampicillin 2g every 4-6 hours or penicillin G 3-4 million units every 4 hours.
- It's essential to complete the full course of antibiotics even if symptoms improve before completion.
- Increased fluid intake is also recommended to help flush bacteria from the urinary tract.
- If symptoms persist after 48-72 hours of treatment, follow-up with a healthcare provider is advised as antibiotic susceptibility testing may be needed to guide alternative therapy, considering the emergence of multidrug-resistant GBS 4.