Lactobacillus mulieris – In Female Bladder

Lactobacillus mulieris belongs to the Lactobacillus genus, which plays a significant role in maintaining a healthy urinary tract. 

Close-up of blue-colored lactobacillus species

The Lactobacillus genre is responsible for producing lactic acid; hence those bacterial species are included in the lactobacillus genus. Lactobacillus species are known as probiotic bacteria as they are considered ‘good bacteria. The functions of the species belonging to this genus are known to protect the gastrointestinal tract and genital area in humans and animals. Protecting the gastrointestinal tract enhances nutrient absorption, maintains the microbiome in the system, and regulates immunomodulation. The body’s insides provide optimal conditions for various harmful pathogens to grow. Therefore, Lactobacillus species acting as good bacteria will maintain the microbiome of the gastrointestinal tract and in the genital area to reduce the growth of harmful bacteria. Lactobacillus mulieris, Lactobacillus gasseri, Lactobacillus iners, Lactobacillus crispatus, etc., are found in the microbiota of the human urinary tract to prevent urinary tract infections (UTI). 

Overview of Lactobacillus mulieris

Lactobacillus mulieris is a gram-positive, coccobacilli-shaped, non-motile, non-spore forming facultatively anaerobic and microaerophile bacteria, as they thrive well in the presence of low oxygen. This bacteria is homofermentative as they only produce a single end product, lactic acid, from metabolizing glucose. They do not have catalase; hence they do not hydrolyze hydrogen peroxide (H2O2) to form water and oxygen. The optimal growth for Lactobacillus mulieris is observed to be at 37°C; however, depending on the pH range of 5-8.5, the temperature required for their development ranges between 30-45°C. The genomic size of this bacteria is recorded to be 1.66Mbp with G+C content in DNA calculated as 34.2 mol%. GC content is an approximate estimation to determine the stability of the DNA and for PCR experimentation. With the help of the GC content estimation, the 16S rRNA gene can be sequenced by designing primers according to the GC content.  

 Close-up of petridish having lactobacillus bacterial culture

The Lactobacillus mulieris was isolated from a urine sample of a healthy woman of reproductive age. The bacterial colony was found to be white, glossy, and circular with 1-2mm in diameter. 16s rRNA sequencing was carried out to determine the identity of the species, thus confirming the bacteria belonging to the genus Lactobacillus. Based on the Average Nucleotide Identity (ANI) and Genome-to-Genome Distance Calculator (GGDC), in silico was observed to be 87.9% and 34.3%, similar to its closest relative, the Lactobacillus jensenii, respectively. Therefore, once Lactobacillus mulieris was considered Lactobacillus jensenii species, it was separated into two different species. 

Functions of Lactobacillus mulieris

Presently, the lactobacillus species in the urinary tract play a primary role for specific pathogens. In addition to protecting the gastrointestinal tract and female genital area by the lactobacillus species, a few lactobacillus species are also responsible for protecting the microbiota in the human urinary tract. For example, Lactobacillus crispatus has been established in women with lower urinary tract symptoms, whereas Lactobacillus jensenii has been observed in women with and without lower urinary tract symptoms. In contrast, Lactobacillus jensenii and Lactobacillus crispatus can inhibit the growth of Escherichia coli which is a uropathogen found in the urinary tract. Therefore, these lactobacillus species can decrease and control the growth of uropathogens responsible for causing sexually transmitted infections. 

Close-up of green lactobacillus bacteria attached 

Lactobacillus jensenii is one of the most commonly found suitable bacterial species in the urinary tract, from which Lactobacillus mulieris was distinguished later. Lactobacillus mulieris was found to have been isolated from women having lower urinary tract symptoms. Since Lactobacillus mulieris was a part of Lactobacillus jensenii, this bacteria was responsible for protecting the urinary tract from harmful pathogens. This is achieved by acting as a barrier against these pathogens, thereby protecting the urinary tract from urogenital infections. As Lactobacillus mulieris is quite similar to Lactobacillus jensenii, their crucial role is to prevent common urinary infections and sexually transmitted infections (STI). 

Asha Rachel Thomas

30/05/2022