Should a lactobacillus urinary tract infection (UTI) be treated in a pregnant woman?

Treatment of Lactobacillus Urinary Infection in Pregnant Women

Lactobacillus in urine should not be treated in pregnant women unless it represents true bacteriuria with symptoms or meets criteria for asymptomatic bacteriuria requiring treatment. 1

Understanding Lactobacillus in the Urinary Tract

• Lactobacillus is typically considered part of the normal vaginal flora and is generally not a pathogenic organism in the urinary tract 1
• Confusion may arise between normal Lactobacillus colonization and true urinary tract infection requiring treatment 1
• The Infectious Diseases Society of America (IDSA) guidelines focus on treatment of asymptomatic bacteriuria with pathogenic organisms, not normal flora like Lactobacillus 2, 1

Criteria for Treatment in Pregnancy

• Pregnant women should be screened for asymptomatic bacteriuria at their first prenatal visit 2, 3

• Treatment is indicated when:

  • There are symptoms of UTI (dysuria, frequency, urgency) 3
  • Asymptomatic bacteriuria is present with ≥10^5 colony-forming units per mL of a single uropathogen 2
  • Group B Streptococcus is present in urine at any colony count 3

• Lactobacillus alone, without symptoms or significant colony counts, does not warrant antimicrobial treatment 1

Evidence Supporting Treatment Decisions

• The 2019 IDSA guidelines strongly recommend screening for and treating asymptomatic bacteriuria in pregnancy, but this applies to pathogenic organisms, not normal flora 2
• Treatment of asymptomatic bacteriuria in pregnancy decreases the risk of pyelonephritis from 20-35% to 1-4% 2
• Antimicrobial treatment of asymptomatic bacteriuria during pregnancy also decreases the frequency of low birth weight infants and preterm delivery 2

Risks of Unnecessary Treatment

• Treating normal Lactobacillus colonization may disrupt the normal microbiome without providing clinical benefit 1
• Unnecessary antibiotic use can lead to adverse effects and development of bacterial resistance 1
• Studies suggest that antimicrobial therapy for asymptomatic bacteriuria was an independent risk factor for developing symptomatic UTI in the year following treatment 2

Appropriate Management Approach

• Obtain a clean-catch midstream urine specimen for culture before starting antibiotics 3
• Confirm that the Lactobacillus represents true bacteriuria (≥10^5 CFU/mL) and not contamination 2
• If the patient is symptomatic with significant bacteriuria, treat according to susceptibility testing 2
• If asymptomatic with significant bacteriuria of a pathogenic organism, treat with a 4-7 day course of appropriate antibiotics 2
• For asymptomatic Lactobacillus in urine without significant colony counts, observation without treatment is appropriate 1

Common Pitfalls to Avoid

• Failing to distinguish between normal Lactobacillus colonization and true bacteriuria requiring treatment 1
• Overtreatment of non-pathogenic organisms, leading to disruption of normal flora and potential for antibiotic resistance 1
• Confusing vaginal Lactobacillus colonization with urinary tract infection 1
• Delaying treatment when true asymptomatic bacteriuria with pathogenic organisms is present 3