What is the treatment for Lactobacillus (lactic acid bacteria) urinary tract infection (UTI)?

Treatment of Lactobacillus UTI

Lactobacillus UTIs generally do not require antibiotic treatment as they are typically considered contaminants or colonizers rather than true pathogens. When Lactobacillus is isolated in urine culture, clinicians should first determine if the patient has true UTI symptoms before initiating any treatment.

Diagnostic Considerations

• Lactobacillus species are normally considered part of the healthy vaginal microbiome and are rarely true uropathogens
• When found in urine cultures, consider:
  • Possible contamination from vaginal flora during collection
  • Colonization without infection
  • True infection (uncommon)

Assessment Algorithm

1. Evaluate for symptoms:

   • Dysuria, frequency, urgency, suprapubic pain
   • Absence of symptoms suggests asymptomatic bacteriuria, which should NOT be treated 1

2. Confirm diagnosis:

   • Obtain urinalysis and urine culture
   • Presence of symptoms plus positive culture warrants treatment, even with low bacterial counts 2
   • Repeat urine culture if symptoms persist beyond 7 days after treatment 1

Treatment Approach

For Symptomatic Lactobacillus UTI:

If the patient has clear UTI symptoms and Lactobacillus is the only isolated organism in significant quantities:

1. First-line antibiotic options 2:

   • Nitrofurantoin 100 mg twice daily for 5 days
   • Trimethoprim-sulfamethoxazole (TMP-SMX) 160/800 mg twice daily for 3 days (if local resistance <20%)
   • Fosfomycin 3 g single dose

2. Dosage adjustment for renal impairment 3:

   • For TMP-SMX:
     • CrCl >30 mL/min: Standard regimen
     • CrCl 15-30 mL/min: Half the usual regimen
     • CrCl <15 mL/min: Not recommended

For Recurrent UTIs with Lactobacillus:

If Lactobacillus is repeatedly isolated in a patient with recurrent UTI symptoms:

1. Consider underlying causes:

   • Anatomical abnormalities
   • Incomplete bladder emptying
   • Urinary catheterization
   • Immunosuppression

2. Prevention strategies:

   • For postmenopausal women: Vaginal estrogen therapy with or without lactobacillus-containing probiotics 1
   • For premenopausal women with post-coital infections: Low-dose antibiotic within 2 hours of sexual activity 1
   • Non-antibiotic alternatives: Methenamine hippurate and/or lactobacillus-containing probiotics 1

Special Considerations

Lactobacillus as Beneficial Bacteria

Interestingly, Lactobacillus species are often used as probiotics to prevent UTIs rather than being treated as pathogens:

• Lactobacillus rhamnosus GR-1 and L. reuteri RC-14 have shown effectiveness in preventing recurrent UTIs 4, 5
• Lactobacillus crispatus has demonstrated ability to reduce intracellular uropathogenic E. coli load in bladder epithelial cells 6
• Women with recurrent UTIs have been found to have reduced bladder Lactobacilli populations compared to healthy women 6

Pitfalls to Avoid

1. Overtreatment: Avoid treating asymptomatic bacteriuria with Lactobacillus, as this promotes antimicrobial resistance 1
2. Misdiagnosis: Don't assume Lactobacillus in urine is always contamination; evaluate symptoms carefully
3. Broad-spectrum antibiotics: Avoid using fluoroquinolones or cephalosporins as first-line therapy due to collateral damage to gut flora 2
4. Prolonged therapy: Use the shortest effective duration of antibiotics to reduce resistance development 2

Conclusion

When Lactobacillus is isolated from urine culture in a symptomatic patient, a short course of nitrofurantoin, TMP-SMX, or fosfomycin is appropriate. However, in many cases, Lactobacillus represents contamination or colonization rather than true infection, and treatment should be reserved for patients with clear UTI symptoms.