Should the Patient Continue Keflex After Symptom Resolution?
Yes, the patient must complete the full course of Keflex (cephalexin) for 7-14 days, and she will also require intrapartum IV antibiotic prophylaxis during labor regardless of completing this treatment. 1, 2
Critical Context: GBS Bacteriuria in Pregnancy
The presence of Group B Streptococcus in urine at any concentration during pregnancy is a marker for heavy genital tract colonization and significantly increases the risk of early-onset neonatal GBS disease. 1 This finding has two distinct management implications:
- Immediate treatment of the acute UTI with a full 7-14 day course of antibiotics 2
- Mandatory intrapartum IV antibiotic prophylaxis during labor, regardless of whether the UTI was treated earlier in pregnancy 1
Why Symptom Resolution After 2 Days Does Not Mean Treatment is Complete
Completing the full antibiotic course is crucial to ensure complete eradication and prevent recurrence. 1 The resolution of symptoms after 2 days of Macrobid does not indicate bacterial eradication—it only reflects symptomatic improvement. 2
Key points about treatment duration:
- The standard treatment course for UTI in pregnancy is 7-14 days 2
- Premature discontinuation may lead to treatment failure or recurrence 1
- Treating the UTI during pregnancy does NOT eliminate GBS colonization from the genitourinary tract—recolonization after oral antibiotics is typical 1
The Dual-Organism Infection Requires Adequate Coverage
This patient has both E. coli and GBS isolated from urine. While Macrobid (nitrofurantoin) has activity against both organisms 3, 4, switching to Keflex (cephalexin) provides:
- Excellent coverage for both E. coli and GBS 2, 3
- Achievement of adequate blood and urinary concentrations 2
- An excellent safety profile in pregnancy 2
Cephalexin is specifically recommended as a first-line alternative for treating UTIs in pregnancy and has demonstrated consistent efficacy against GBS. 2, 3
Intrapartum Prophylaxis Remains Mandatory
Even after completing the full course of antibiotics for this UTI, this patient will require IV antibiotic prophylaxis during labor. 1 The recommended regimen is:
- Penicillin G 5 million units IV initially, then 2.5 million units IV every 4 hours until delivery (preferred) 1
- Alternative: Ampicillin 2 g IV initially, then 1 g IV every 4 hours until delivery 1
This intrapartum prophylaxis must be administered ≥4 hours before delivery for maximum effectiveness, resulting in a 78% reduction in early-onset neonatal GBS disease. 1
Common Pitfall to Avoid
Do not assume that treating the UTI eliminates the need for intrapartum prophylaxis—this is a common and dangerous error. 1 Women with GBS bacteriuria at any point during pregnancy are presumed to be heavily colonized and automatically qualify for intrapartum prophylaxis regardless of prior treatment. 1
Documentation and Communication
Ensure that laboratory reports of GBS bacteriuria are communicated to both the anticipated site of delivery and the ordering provider so that intrapartum prophylaxis is not missed. 1