Name: urogenital microbiota and urinary health
Uploaded: 2026-03-12T13:35:59.000Z
Duration: 1 min 28 s
Channel: JoVE

Healthy adult bladders may contain low-biomass microbial communities, including facultative anaerobes like Proteus mirabilis and E. coli.Proteus mirabilis produces urease, which breaks down urea into ammonia. This sometimes causes an abnormal increase in urine pH, leading to the formation of stones.The distal urethra also hosts similar bacterial species in higher abundance. When pH or microbiota balance shifts, some of these species can become pathogenic.The penile microbiota harbors bacterial genera like Corynebacterium and Staphylococcus.In the vagina, low glycogen and neutral pH, especially before puberty, favor colonization by staphylococci, streptococci, and corynebacteria.Whereas during reproductive years, the vaginal microbiota is dominated by members of the genus Lactobacillus.This dominance is sustained due to a mildly acidic environment created by Lactobacillus species which ferments glycogen into lactic acid.The resulting low pH also largely inhibits opportunistic pathogens like Candida species and E. coli.

microbiota of the urogenital tract

Microbiota of the Urogenital Tract

The human urogenital system, once thought to be sterile in healthy individuals, is now recognized as a complex microbial habitat. Advancements in molecular sequencing techniques have revealed that even in healthy adults, the kidneys and bladder harbor microbial populations similar to those found in the distal urethra, albeit in much lower abundance. These resident microorganisms, while generally innocuous, can become opportunistic pathogens under conditions that alter the urogenital environment, such as shifts in pH or disruptions in the microbial balance.Microbial Composition of the Urethra and Pathogenicity The distal urethra hosts a range of bacterial species, including Escherichia coli and Proteus mirabilis. These bacteria are typically present in small quantities but can proliferate and cause infections when the urogenital environment is disrupted. A notable pathogenic mechanism involves the urease enzyme produced by P. mirabilis, which catalyzes the hydrolysis of urea into ammonia. The production of ammonia from urea hydrolysis elevates the pH of urine, potentially creating favorable conditions for the precipitation of minerals and the formation of kidney stones.Sex-Specific Differences in Urogenital Microbiota In addition to the urethral microbiota, sex-based differences exist in the composition of the urogenital microbiota. In males, the penile microbiota is dominated by Lactobacillus and Streptococcus species. The vaginal microbiota is also dominated by Lactobacillus. It encompasses over one hundred different genera. Among these, Lactobacillus acidophilus plays a key role by fermenting glycogen to produce lactic acid, thereby maintaining vaginal pH within a mildly acidic range. This acidic environment acts as a natural defense against opportunistic pathogens such as Candida sp. and E. coli.Estrogen plays a crucial role in maintaining this environment by promoting glycogen deposition in vaginal epithelial cells. Before puberty and after menopause, decreased estrogen levels result in lower glycogen availability and a shift to a more neutral vaginal pH. This altered environment supports the growth of other microbial groups, including staphylococci, streptococci, and corynebacteria, thereby reflecting dynamic changes in the microbiota across the female lifespan.

The human urogenital system, once thought to be sterile in healthy individuals, is now recognized as a complex microbial habitat. Advancements in ...

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Microbiology

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Human Microbiome and Virome

KEY TERMS AND CONCEPTS

urogenital microbiota and urinary health

The urogenital tract contains a natural community of microorganisms, and healthy kidneys and bladder are not sterile. Molecular sequencing has shown that these microbes are present even in healthy adults. Their numbers are low compared with the distal urethra, but they still form part of the normal microbial habitat.

Most of these resident microbes are harmless, but they can become opportunistic pathogens when the urogenital environment changes. Shifts in pH and disruptions in microbial balance can allow them to grow. The distal urethra can contain bacteria such as Escherichia coli and Proteus mirabilis. When conditions favor growth, these bacteria can contribute to infection.

Proteus mirabilis has an important enzyme called urease. Urease breaks down urea into ammonia. The ammonia raises urine pH, which can support mineral precipitation and may lead to kidney stone formation.

The urogenital microbiota also differs by sex. In males, the penile microbiota is dominated by Lactobacillus and Streptococcus species. The vaginal microbiota is also dominated by Lactobacillus, and it includes more than one hundred genera. Lactobacillus acidophilus helps by fermenting glycogen to make lactic acid, which keeps vaginal pH mildly acidic.

This acidic environment helps protect against opportunistic pathogens such as Candida species and E. coli. Estrogen is important for maintaining this defense because it promotes glycogen buildup in vaginal epithelial cells. Before puberty and after menopause, lower estrogen levels reduce glycogen availability and make vaginal pH more neutral. That change supports other microbial groups, including staphylococci, streptococci, and corynebacteria, and it shows how the microbiota changes across the female lifespan.

Urogenital Microbiota and Urinary Health

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The urogenital tract contains a natural community of microorganisms, and healthy kidneys and bladder are not sterile. Molecular sequencing has shown that these microbes are present even in healthy adults. Their numbers are low compared with the distal urethra, but they still form part of the normal microbial habitat. Most of these resident microbes are harmless, but they can become opportunistic pathogens when the urogenital environment changes. Shifts in pH and disruptions in microbial...

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key terms and concepts

Learn how microbes in the urogenital tract can stay harmless or cause infection, and how urine pH, urease, and estrogen shape urinary health.

Urogenital Microbiota and Urinary Health | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Urogenital Microbiota and Urinary Health

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