Treatment of Lactobacillus-Positive Urine Cultures
Lactobacillus species isolated from urine in otherwise healthy individuals should not be treated with antibiotics, as these organisms are not considered clinically relevant uropathogens and likely represent contamination or colonization rather than true infection. 1
Key Clinical Principles
Lactobacillus is NOT a Uropathogen
- Lactobacillus species, along with coagulase-negative staphylococci and Corynebacterium species, are explicitly not considered clinically relevant urine isolates in otherwise healthy individuals. 1
- These organisms are normal commensals of the vaginal and periurethral flora and their presence in urine typically indicates specimen contamination during collection rather than true urinary tract infection. 1
When Lactobacillus Appears in Urine Culture
If a patient has symptoms of UTI with Lactobacillus isolated:
- Repeat the urine culture with meticulous collection technique (preferably catheterized specimen) to rule out contamination before considering any treatment. 1
- If symptoms persist despite negative repeat culture or culture showing only Lactobacillus, investigate alternative diagnoses for urinary symptoms rather than treating the Lactobacillus. 1
If the patient is asymptomatic with Lactobacillus in urine:
- Do not treat asymptomatic bacteriuria, as this fosters antimicrobial resistance and increases the number of recurrent UTI episodes. 1
- This principle applies even in patients with recurrent UTI history. 1
Important Caveats
Avoid Misclassification
- Do not classify patients with Lactobacillus-positive cultures as having "complicated UTI", as this leads to inappropriate use of broad-spectrum antibiotics with prolonged treatment durations. 1
- Reserve the "complicated UTI" designation for patients with structural/functional urinary tract abnormalities, immunosuppression, or pregnancy. 1
Collection Technique Matters
- Lactobacillus isolation often reflects poor specimen collection technique, particularly in voided specimens from women where vaginal flora contamination is common. 1
- A properly collected specimen (midstream clean-catch or catheterized) significantly reduces the likelihood of Lactobacillus contamination. 1
The Role of Lactobacillus in UTI Prevention (Not Treatment)
While Lactobacillus should not be treated when found in urine, these organisms actually play a protective role:
- Lactobacillus-containing probiotics can be considered as a non-antibiotic alternative for prevention of recurrent UTIs, particularly in postmenopausal women (with vaginal estrogen) or as an alternative to antibiotic prophylaxis. 1
- Vaginal administration of Lactobacillus suppositories may reduce UTI recurrence rates following antimicrobial therapy. 2
- However, the evidence quality for oral Lactobacillus probiotics remains limited, with most studies showing inconsistent results. 1