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).

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

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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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