Lactobacillus in Urine

Julian Selemin
Julian Selemin
March 31, 2023
min read
Technically reviewed by: 
Patricia Radecka
Lactobacillus in Urine

What Is Lactobacillus?

Lactobacillus (plural lactobacilli) is a type of bacterium present in various places of the human body, including the mouth, digestive system, and, most importantly, the vagina. There, it plays a crucial role in defending the reproductive system from harmful bacteria and fungi. As such, it forms part of what’s called the “nonpathogenic flora” — the microorganisms living in your body that benefit your health.1

Unlike what many people think, Lactobacillus isn’t only present in the reproductive system. Experts state that this bacterium is present all over the female genitals, including the urinary tract. The conjunction of the urinary and reproductive systems is known as the urogenital tract.2

How Does Lactobacillus Work?

The vaginal microenvironment is complex and delicate, with many microorganisms involved in keeping the area free of harmful pathogens. Lactobacillus is arguably the most essential component of this flora, playing several roles against different threats.

One of the primary roles of lactobacilli is to produce lactic acid — a naturally occurring compound found in the brain, tissues, and muscles. Lactic acid acidifies the vagina, reducing its pH*. This creates a hostile environment for the growth of harmful bacteria, viruses, and fungi.

Lactobacilli also stimulate the vagina to create several compounds, such as antimicrobial peptides, that help combat pathogens. At the same time, these bacteria compete with external microorganisms, preventing their growth through a process called “competitive rejection."3

Is Lactobacillus in Urine Normal?

The false belief that urine is completely sterile has led many people to believe that finding any kind of microorganism in a test indicates something is wrong. However, finding Lactobacillus in a urine culture is completely normal and not necessarily a sign of a urinary tract infection (UTI).1, 2

Recent research shows that Lactobacillus crispatus, Lactobacillus iners, and Lactobasillus gasseri are all frequently found in the urogenital flora of healthy women. However, the abundance of these bacteria can vary depending on each person’s age, health conditions, and several other factors.1

It’s essential to keep in mind that many doctors will dismiss lactobacilli in urine as contaminants. As a result, they may ask you to repeat the collection process more carefully, taking the necessary precautions to avoid contamination by the vaginal flora.4

It’s unclear how many colonies per milliliter (the measuring standard for urine tests) are considered normal for lactobacilli. Each lab will determine the exact number depending on its testing protocols, but they generally are close to these values:5

  • Less than 10,000 colonies — negative result
  • Between 10,000 and 100,000 colonies — intermediate result
  • More than 100,000 — positive result

Getting a negative result regarding Lactobacillus can be worrying, as it play a key role in urogenital health. For this reason, many women choose to add a Lactobacillus tablet to each meal to reinforce their flora.

Usually, getting a positive result for any bacteria is a sign of a health problem — most commonly, a UTI. Yet, due to the beneficial nature of lactobacilli, it’s best to check with a doctor before getting worried about a positive Lactobacillus result.

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Is It Possible to Get a Lactobacillus UTI?

Lactobacilli are often touted for their beneficial role — but recent research shows that it’s possible to get a Lactobacillus-related UTI. In particular, there have been three case reports about this situation, two for male patients and one for a female patient.4, 6

Researchers point out that Lactobacillus UTIs are exceedingly rare. They mostly appear in patients with immunocompromising conditions (such as HIV), dental complications, or gastrointestinal problems.4

Fortunately, the three patients recovered well after taking specific medications to combat the overgrowth of lactobacilli. Yet, their case reports have been useful for identifying at least seven pathogenic (harmful) lactobacilli:6

  • L. acidophilus
  • L. gasseri
  • L. casei
  • L. paracasei
  • L. rhamnosus
  • L. delbrueckii
  • L. plantarum

Treatment of Lactobacillus UTI

Due to the low prevalence of Lactobacillus-related UTIs, experts haven’t been able to identify a standard treatment. The most effective Lactobacillus UTI treatment seems to be antimicrobials, which help combat the excess bacteria in your urogenital tract. These may include:4, 6

  • Amoxicillin
  • Ciprofloxacin
  • Clarithromycin
  • Cefotaxime

Depending on your flora's reaction to antimicrobials, your doctor may prescribe other medications or lifestyle changes. In general, Lactobacillus UTIs resolve in about two weeks with no further complications for the patient.4, 6


Lactobacillus is one of the most important bacteria for your vaginal flora, helping you keep your urogenital tract healthy and free of pathogens. This means it’s completely normal to find Lactobacillus species in urine.

There have been cases of Lactobacillus-related UTIs, but they are very uncommon and cause no severe consequences after treatment. Nevertheless, if you’re in doubt about your urine Lactobacillus levels, make sure to check with a doctor.


1. Kim, Jun-Mo & Park, Yoo-Jin. (2018). Lactobacillus and urine microbiome in association with urinary tract infections and bacterial vaginosis. Urogenital Tract Infection. 13. 7.  

2. Pearce, M. M., Hilt, E. E., Rosenfeld, A. B., Zilliox, M. J., Thomas-White, K., Fok, C., Kliethermes, S., Schreckenberger, P. C., Brubaker, L., Gai, X., & Wolfe, A. J. (2014). The female urinary microbiome: a comparison of women with and without urgency urinary incontinence. mBio, 5(4), e01283-14.

3. Mei, Z., & Li, D. (2022). The role of probiotics in vaginal health. Frontiers in Cellular and Infection Microbiology, 12, 963868.

4. Darbro, B. W., Petroelje, B. K., & Doern, G. V. (2009). Lactobacillus delbrueckii as the cause of urinary tract infection. Journal of Clinical Microbiology, 47(1), 275–277.

5. Urine Culture and Sensitivity | Lab Tests. (n.d.). GLOWM. Retrieved February 23, 2023.

6. Maillet, F., Passeron, A., Podglajen, I., Ranque, B., & Pouchot, J. (2019). Lactobacillus delbrueckii urinary tract infection in a male patient. Medecine et Maladies Infectieuses, 49(3), 226–228.

*We are grateful to Verroline Fanijten from the Netherlands, who helped identify a mistake in the article and assisted us in correcting it on October 27, 2023. The previous version of the article erroneously reported that lactic acid acidifies the vagina, elevating its pH. The correct version is that lactic acid helps to reduce the pH. We sincerely apologize for the mistake and extend our gratitude to Verroline for her assistance. Thank you, Verroline!

About the Author
Julian Selemin

Julian Selemin is a freelance writer with a burning passion for learning new languages. He has a BA in Languages and is currently majoring in Contemporary Music — however, research is one of his strongest points, so he also likes to write outside of those topics. His writing niches include medicine and alternative medicine, music, and business.

About the Reviewer
This blog was
Technically reviewed by: 
Patricia Radecka

Patricia Radecka led the editorial review for this blog.

Diagnox Staff consists of a multidisciplinary team of scientists, content writers, and healthcare professionals with an expertise to create and review high-quality, informative, accurate, and easy-to-understand content for both professionals and everyday readers. Our staff follows strict guidelines to ensure the credibility and authenticity of the information, reviewing them independently and verifying them by various scientific and technical sources to ensure accuracy. Our review team believes in delivering knowledge free from bias to improve public health and well-being.

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