Should a pregnant patient with asymptomatic bacteriuria (presence of bacteria in urine) and leukocytes in urine be treated with antibiotics?

Treatment of Asymptomatic Bacteriuria in Pregnancy with Leukocytes in Urine

Pregnant patients with asymptomatic bacteriuria and leukocytes in urine should be treated with antibiotics, regardless of the absence of urinary symptoms. 1, 2

Rationale for Treatment

The presence of leukocytes (pyuria) in a pregnant patient's urine, even without symptoms, warrants antibiotic treatment due to:

• Untreated asymptomatic bacteriuria in pregnancy carries a 20-30 fold increased risk of developing pyelonephritis compared to women without bacteriuria 2
• Treatment decreases the risk of pyelonephritis from 20-35% to 1-4% 2
• Antibiotics reduce the risk of preterm birth (from approximately 53 per 1000 to 14 per 1000) 1
• Antibiotics lower the chance of very low birth weight (from approximately 137 per 1000 to 88 per 1000) 1

While vaginal discharge alone is not an indication for treatment of bacteriuria, the presence of leukocytes in urine suggests an inflammatory response that should not be ignored in pregnancy.

Diagnostic Approach

• Urine culture is the gold standard for diagnosis of bacteriuria 2
• Bacteriuria is defined as:
  • 2 consecutive voided urine specimens with isolation of the same bacterial strain in quantitative counts ≥10^5 CFU/mL, or
  • A single catheterized urine specimen with 1 bacterial species isolated in a quantitative count ≥10^2 CFU/mL 2
• Pyuria (leukocytes in urine) alone is not diagnostic but increases suspicion when bacteriuria is present 1, 3

Treatment Recommendations

First-line antibiotic options:

• Nitrofurantoin 100mg BID for 4-7 days (safe in pregnancy) 2, 3
• Cephalexin 500mg QID for 4-7 days 2
• Ampicillin 500mg QID for 4-7 days (if pathogen is susceptible) 2

Duration of therapy:

• 4-7 days of treatment is recommended rather than single-dose therapy 1, 2
• Seven days of therapy has been shown to be more effective than single-dose therapy in preventing adverse outcomes like lower birth weight 1

Antibiotics to avoid:

• Fluoroquinolones (contraindicated in pregnancy) 2, 3
• Tetracyclines (contraindicated in pregnancy) 2
• Trimethoprim-sulfamethoxazole in first and third trimesters 2

Follow-up

• Obtain follow-up urine culture 1-2 weeks after completing therapy to ensure clearance of bacteriuria 2
• If bacteriuria persists, retreatment with a different antibiotic based on susceptibility is recommended 2
• Periodic screening for recurrent bacteriuria should be undertaken following therapy 2

Common Pitfalls to Avoid

1. Ignoring asymptomatic bacteriuria in pregnancy: Unlike in non-pregnant populations where asymptomatic bacteriuria is often left untreated, in pregnancy it requires treatment due to significant risks 1, 2

2. Using inadequate treatment duration: Single-dose therapy is less effective than 4-7 day regimens for clearing bacteriuria in pregnancy 1

3. Failing to follow up: Not confirming clearance of bacteriuria after treatment can lead to persistent infection and complications 2

4. Misinterpreting pyuria: While pyuria alone doesn't always indicate infection, in pregnancy with bacteriuria it should be taken seriously 3

5. Using inappropriate antibiotics: Some antibiotics that are commonly used for UTIs in non-pregnant patients are contraindicated during pregnancy 2, 3

By following these evidence-based recommendations, you can effectively manage asymptomatic bacteriuria with leukocyturia in pregnancy and reduce the risk of serious maternal and fetal complications.