From the Guidelines
Penicillin G or ampicillin are the first-line antibiotics for treating Streptococcus agalactiae (Group B streptococcus) urinary tract infections. For uncomplicated UTIs, ampicillin 500 mg orally four times daily for 7-10 days is typically recommended 1. For more severe infections, intravenous penicillin G 2-4 million units every 4-6 hours or ampicillin 1-2 g every 4-6 hours may be necessary. In patients with penicillin allergy, first-generation cephalosporins like cefazolin can be used if the allergy is not severe 1. For patients with severe penicillin allergy, vancomycin 15-20 mg/kg IV every 8-12 hours is an appropriate alternative. Clindamycin may also be used in some cases at 300-450 mg orally four times daily. Group B streptococcus remains highly susceptible to penicillins because these antibiotics effectively target the bacterial cell wall synthesis, which is essential for bacterial survival. Treatment duration should be individualized based on symptom resolution and clinical response, but typically ranges from 7-14 days depending on infection severity. Urine culture and susceptibility testing should guide therapy, especially in complicated cases or treatment failures. Some key points to consider in the management of Streptococcus agalactiae UTIs include:
- Women with GBS isolated from the urine in any concentration during their current pregnancy should receive intrapartum chemoprophylaxis because such women usually are heavily colonized with GBS and are at increased risk of delivering an infant with early-onset GBS disease 1.
- Women with symptomatic or asymptomatic GBS urinary tract infection detected during pregnancy should be treated according to current standards of care for urinary tract infection during pregnancy 1.
- Intrapartum chemoprophylaxis for penicillin-allergic women takes into account increasing resistance to clindamycin and erythromycin among GBS isolates 1. The most recent and highest quality study 1 provides the basis for these recommendations, emphasizing the importance of appropriate antibiotic selection and treatment duration in managing Streptococcus agalactiae UTIs.
From the FDA Drug Label
In streptococcal infections, therapy must be sufficient to eliminate the organism (10 days minimum); otherwise the sequelae of streptococcal disease may occur. The recommended antibiotic for treating Streptococcus agalactiae (Group B streptococcus) urinary tract infections (UTI) is ampicillin. The treatment should be sufficient to eliminate the organism, with a minimum duration of 10 days 2.
- Ampicillin is the recommended treatment for streptococcal infections, including Streptococcus agalactiae.
- The treatment duration should be at least 10 days to ensure the elimination of the organism.
- It is essential to complete the full course of therapy to prevent the development of resistance and reduce the likelihood of sequelae.
From the Research
Recommended Antibiotics for Treating Streptococcus agalactiae UTI
- The recommended antibiotics for treating Streptococcus agalactiae (Group B streptococcus) urinary tract infections (UTI) include:
- Ampicillin 3, 4, 5, 6
- Penicillin 4, 6
- Vancomycin 4, 6
- Ceftriaxone 4
- Levofloxacin 4
- Linezolid 4
- Cefotaxime 4 (although one isolate showed resistance)
- Erythromycin 3 (although 10.4% of isolates showed resistance in one study 4)
- Clindamycin 3 (although 23.4% of isolates showed resistance in one study 4 and 77.34% in another study 6)
- Rifampicin 3
- Augmentin 3
- Cephalothin 3
- Lincomycin 3
- Chloramphenicol 3
Important Considerations
- The choice of antibiotic should be based on the results of antibiotic sensitivity testing 3, 4, 5, 6
- The presence of reservoirs of infection (vagina, urethra, gastrointestinal tract) should be established to ensure successful treatment 3
- Local treatment with vaginal lavages may be necessary in some cases 3
- Monitoring of antibiotic resistance patterns is essential to guide treatment decisions 4, 6