What is the recommended treatment for a breastfeeding mother with a Group B strep (Streptococcus agalactiae) urinary tract infection (UTI)?

Treatment for Group B Strep UTI in a Breastfeeding Mother

Treat the GBS urinary tract infection with standard oral antibiotics (amoxicillin 500 mg every 8 hours or penicillin VK 500 mg every 6 hours for 7-10 days), which are safe during breastfeeding, and if the patient is pregnant, she will also require intrapartum antibiotic prophylaxis during labor regardless of whether the UTI was treated earlier in pregnancy. 1, 2

First-Line Treatment Options

• Amoxicillin is the preferred oral agent for outpatient treatment of GBS UTI, typically dosed at 500 mg every 8 hours or 875 mg every 12 hours for 7-10 days 3, 4
• Penicillin VK is an acceptable alternative, dosed at 500 mg every 6 hours 5, 4
• Both penicillin and amoxicillin are considered safe during breastfeeding, as most antibiotics in clinical use are suitable for nursing mothers 6
• Complete the full prescribed course to ensure complete eradication and prevent recurrence 1, 2

Treatment for Penicillin-Allergic Patients

• For patients with non-severe penicillin allergy (no history of anaphylaxis, angioedema, or urticaria), cephalexin 500 mg every 6 hours is the preferred alternative 1, 2
• For patients at high risk for anaphylaxis, use clindamycin 300-450 mg every 6 hours orally, but ONLY if susceptibility testing confirms the isolate is susceptible 1, 7
• If clindamycin susceptibility is unknown or the isolate is resistant, consider alternative agents or consult infectious disease 1, 2

Critical Considerations for Pregnant Breastfeeding Mothers

• Any concentration of GBS bacteriuria during pregnancy (even if asymptomatic) requires both immediate treatment of the UTI AND intrapartum antibiotic prophylaxis during labor 8, 1, 2
• The patient will need intrapartum prophylaxis even if the UTI is successfully treated now, because GBS bacteriuria indicates heavy genital tract colonization 8, 1
• Vaginal-rectal screening at 35-37 weeks is NOT necessary for women with documented GBS bacteriuria during pregnancy 8, 1
• Do NOT use oral antibiotics to attempt eradication of GBS colonization outside of treating active infection—this is ineffective and promotes resistance 8, 1

Breastfeeding Safety

• Temporary cessation of breastfeeding for 24 hours may be considered if the mother has active GBS bacteremia or mastitis, but this is rarely necessary for simple UTI 9
• In most cases of maternal bacterial infection, breast milk is not an important mode of transmission, and continuation of breastfeeding is in the best interest of both infant and mother 9
• The infant has likely already been exposed by the time of diagnosis, and stopping breastfeeding only deprives the infant of nutritional and immunologic benefits 9

Important Clinical Pitfalls

• Do not underdose or allow premature discontinuation of therapy, as this leads to treatment failure and recurrence 1, 2
• Do not forget intrapartum prophylaxis if the patient is pregnant—failure to provide this increases the risk of early-onset neonatal GBS disease 8, 1
• Do not attempt to "decolonize" the patient with prolonged antibiotic courses outside of treating active infection—this is ineffective and harmful 8, 1
• For penicillin-allergic patients at high risk for anaphylaxis, always obtain susceptibility testing before using clindamycin, as approximately 20% of GBS isolates are resistant 1, 2