Do you treat a lactobacillus (lactobacillus)-positive urine culture in pregnancy?

Management of Lactobacillus in Urine Culture During Pregnancy

Lactobacillus in urine culture during pregnancy does not require antibiotic treatment as it is typically considered a contaminant rather than a true uropathogen requiring intervention. 1

Understanding Lactobacillus in Urine Culture

Lactobacillus is generally not considered a significant uropathogen in pregnancy. The Infectious Diseases Society of America (IDSA) guidelines specifically recommend screening for and treating asymptomatic bacteriuria (ASB) in pregnancy, but this applies to true uropathogens, not contaminants like Lactobacillus 2, 1.

When evaluating urine cultures in pregnancy, it's important to distinguish between:

• True uropathogens (E. coli, Klebsiella, etc.) that require treatment
• Contaminants (like Lactobacillus) that do not require treatment

Evidence-Based Approach to Bacteriuria in Pregnancy

Screening Recommendations

• IDSA strongly recommends screening all pregnant women for ASB with urine culture at least once in early pregnancy (typically 12-16 weeks) 2, 1
• Diagnosis should be based on properly collected urine specimens that minimize contamination 2
• For women, ASB is defined as two consecutive voided urine specimens with isolation of the same bacterial strain in quantitative counts ≥10^5 CFU/mL 2

Treatment Decision Algorithm

1. Is the organism a recognized uropathogen?

   • True uropathogens (E. coli, Klebsiella, etc.): Treat with appropriate antibiotics
   • Lactobacillus and other likely contaminants: No treatment required

2. Is the patient symptomatic?

   • Symptomatic (dysuria, frequency, urgency): Treat empirically while awaiting culture results
   • Asymptomatic with Lactobacillus only: No treatment required

3. Is there evidence of true bacteriuria?

   • Positive urine culture with ≥10^5 CFU/mL of a uropathogen: Treat
   • Lactobacillus alone, regardless of count: No treatment required

Potential Pitfalls in Management

1. Overtreatment risks:

   • Unnecessary antibiotic exposure during pregnancy
   • Potential side effects and antimicrobial resistance
   • Disruption of normal vaginal flora

2. Misinterpretation of results:

   • Lactobacillus is a normal component of vaginal flora and often represents contamination
   • Presence of Lactobacillus alone does not indicate infection requiring treatment

3. Follow-up considerations:

   • If concerned about contamination, consider repeating the urine culture with proper collection technique
   • Continue routine prenatal care and standard ASB screening

Special Considerations

If Lactobacillus is found alongside true uropathogens in significant quantities, treatment should target the uropathogen according to susceptibility testing. The IDSA recommends 4-7 days of antimicrobial treatment for confirmed ASB in pregnancy 2.

Remember that while ASB with true uropathogens requires treatment in pregnancy to prevent complications like pyelonephritis, preterm birth, and low birth weight 2, 3, treating contaminants like Lactobacillus provides no benefit and may cause harm through unnecessary antibiotic exposure.