{"history":[],"article":{"id":"559f9040-c70c-49fd-874e-fdd58c88cb8a","title":"Vaginal flora","slug":"vaginal-flora","content":":::summary\n:::\n\n# \n**Vaginal flora**, **[vagina](https://bliptext.com/articles/vagina)l microbiota** or **[vagina](https://bliptext.com/articles/vagina)l microbiome** are the [microorganisms](https://bliptext.com/articles/microorganisms) that colonize the [vagina](https://bliptext.com/articles/vagina).\nThey were discovered by the German gynecologist [Albert Döderlein](https://bliptext.com/articles/albert-d-derlein) in 1892 and are part of the overall [human flora](https://bliptext.com/articles/human-flora).\nThe amount and type of bacteria present have significant implications for an individual's overall health.\nThe primary colonizing bacteria of a healthy individual are of the genus [Lactobacillus](https://bliptext.com/articles/lactobacillus), such as [L. crispatus](https://bliptext.com/articles/lactobacillus-crispatus), and the [lactic acid](https://bliptext.com/articles/lactic-acid) they produce is thought to protect against infection by pathogenic species.\n# [Lactobacilli and a vaginal squamous cell | upload.wikimedia.org/wikipedia/commons/7/7d/Lactobacillus///sp///01.png]\n\n# Lactobacilli\nThe primary colonizing bacteria of a healthy individual are of the genus [Lactobacillus](https://bliptext.com/articles/lactobacillus) (90–95%), the most common being [L. crispatus](https://bliptext.com/articles/lactobacillus-crispatus), [L. iners](https://bliptext.com/articles/lactobacillus-iners), [L. jensenii](https://bliptext.com/articles/lactobacillus-jensenii), and [L. gasseri](https://bliptext.com/articles/lactobacillus-gasseri).\nSince the first description of lactobacilli by Döderlein, lactobacilli have been generally considered the gatekeepers of the vaginal ecosystem.\nLactobacilli have been shown to inhibit in vitro growth of pathogenic microorganisms, e.g. [Bacteroides fragilis](https://bliptext.com/articles/bacteroides-fragilis), [Escherichia coli](https://bliptext.com/articles/escherichia-coli), [Gardnerella vaginalis](https://bliptext.com/articles/gardnerella-vaginalis), Mobiluncus spp., [Neisseria gonorrhoeae](https://bliptext.com/articles/neisseria-gonorrhoeae), [Peptostreptococcus anaerobius](https://bliptext.com/articles/peptostreptococcus-anaerobius), [Prevotella bivia](https://bliptext.com/articles/prevotella-bivia) and [Staphylococcus aureus](https://bliptext.com/articles/staphylococcus-aureus).\nIt is generally accepted that this is achieved mainly through the action of lactic acid.\nMoreover, lactobacilli normally help to prevent long-term colonization of the vagina by adhering to vaginal epithelial cells.\nThis usually reduces pathogens from infecting to the [vaginal epithelium](https://bliptext.com/articles/vaginal-epithelium).\nNext to lactic acid production and competition for adherence, other antagonistic mechanisms include [hydrogen peroxide](https://bliptext.com/articles/hydrogen-peroxide) (a broad-spectrum antimicrobial) and [bacteriocins](https://bliptext.com/articles/bacteriocin) (target-specific antimicrobials) production.\n\n## pH and lactic acid\nLow pH is generally accepted to be the main mechanism controlling the composition of the vaginal microflora.\nAlthough the lactic acid produced by lactobacilli contributes to the vaginal acidity, it is still not proven to be the primary source of low vaginal pH, but the fact remains that most lactobacilli thrive best at a pH < 3.5.\nNormal vaginal pH is considered to be under 4.5 with a range of 3.8 to 4.4.\n# [Glycogen is the complex form of sugar present in the vaginal epithelium that is metabolized into lactic acid | upload.wikimedia.org/wikipedia/commons/4/47/Glycogen///structure.svg]\n\n## Hydrogen peroxide\nProduction of hydrogen peroxide (H₂O₂) is a proposed mechanism for bacterial antagonism in vitro, inhibiting growth of microorganisms via direct interaction or via human myeloperoxidase.\nHowever, in vivo, the role of peroxide is uncertain.\nUnder optimal anaerobic growth conditions, physiological concentrations of lactic acid inactivated the [BV-associated pathogens](https://bliptext.com/articles/bacterial-vaginosis) without affecting the vaginal lactobacilli.\nAlthough the hydrogen peroxide production of lactobacilli has been considered as an important antimicrobial component, contributing to the colonization resistance provided by lactobacilli, and although there seems to be a link between H₂O₂-producing lactobacilli and normal vaginal microflora, recent data do not support this role for H₂O₂.\nExperimentally, hydrogen peroxide-producing lactobacilli have been shown to inactivate [HIV-1](https://bliptext.com/articles/hiv), [herpes simplex virus type 2](https://bliptext.com/articles/herpes-simplex-virus) (HSV-2), [Trichomonas vaginalis](https://bliptext.com/articles/trichomonas-vaginalis), [G. vaginalis](https://bliptext.com/articles/gardnerella-vaginalis), [P. bivia](https://bliptext.com/articles/prevotella-bivia) and [E. coli](https://bliptext.com/articles/escherichia-coli).\nO'Hanlon and Baeten found that 96% of [Lactobacillus](https://bliptext.com/articles/lactobacillus) species from a healthy vaginal ecosystem produced H₂O₂ ([L. jensenii](https://bliptext.com/articles/lactobacillus-jensenii) and [L. vaginalis](https://bliptext.com/articles/lactobacillus-vaginalis) produce the highest levels of H₂O₂), whereas only 6% of the lactobacilli recovered from women with BV produced H₂O₂.\nIn agreement with this, [L. iners](https://bliptext.com/articles/lactobacillus-iners), most frequently associated with disturbed vaginal microflora, is a poor producer of H₂O₂.\nVaginal colonization by H₂O₂-producing lactobacilli has been associated with a decrease in the occurrence of [bacterial vaginosis](https://bliptext.com/articles/bacterial-vaginosis) (BV).\nHowever, more recently O'Hanlon et al. demonstrated that cervicovaginal fluid and semen have a significant H₂O₂-blocking activity and they later demonstrated that physiological concentrations of H₂O₂ below 100 μM fail to inactivate any of the 17 tested BV-associated bacteria, e.g. [A. vaginae](https://bliptext.com/articles/atopobium-vaginae), [G. vaginalis](https://bliptext.com/articles/gardnerella-vaginalis), Mobiluncus spp., [P. bivia](https://bliptext.com/articles/prevotella-bivia), [P. corporis](https://bliptext.com/articles/prevotella), [Mycoplasma hominis](https://bliptext.com/articles/mycoplasma-hominis), even in the presence of human [myeloperoxidase](https://bliptext.com/articles/myeloperoxidase), known to increase the microbicidal activity of H₂O₂.\nOnly supraphysiologic concentrations of exogenous H₂O₂ (0.34% w/v, 100 mM) were sufficient to inactivate BV-associated bacteria at which concentration it more potently inactivated vaginal lactobacilli ([L. crispatus](https://bliptext.com/articles/lactobacillus-crispatus), [L. gasseri](https://bliptext.com/articles/lactobacillus-gasseri), [L. iners](https://bliptext.com/articles/lactobacillus-iners) and [L. jensenii](https://bliptext.com/articles/lactobacillus-jensenii)).\nA concentration of 100 mM H₂O₂ is approximately 50-fold higher than lactobacilli are capable of producing even under optimal aerobic, low-antioxidant conditions, and approximately 5,000-fold higher than the estimated H₂O₂ concentration in vivo. Even more remarkable, the addition of only 1% vaginal fluid blocked the microbicidal activity of 1 M H₂O₂.\nPossible explanations may be that cervicovaginal fluid and semen contain proteins, glycoproteins, polysaccharides, lipids, and other molecules with the potential to react with and inactivate H₂O₂.\nIn addition, the vagina is hypoxic most of the time, whereas lactobacilli require oxygen to produce hydrogen peroxide.\nIt is also remarkable that catalase, which provides bacteria protection against toxic H₂O₂, is absent in lactobacilli, and as such they would be unprotected against their own H₂O₂ production.\nConsequently, hydrogen peroxide production may not be the major mechanism of defense.\n\n## Bacteriocins\nVaginal lactobacilli produce antimicrobial peptides, i.e. bacteriocins such as lactocin 160 and crispasin.\nwith inhibitory activity ranging from narrow (closely related Lactobacillus species) to broad (diverse groups of bacteria, including [G. vaginalis](https://bliptext.com/articles/gardnerella-vaginalis) and [P. bivia](https://bliptext.com/articles/prevotella-bivia)), and bacteriocin-like substances, with a broader spectrum of activity than bacteriocins (e.g. a heat-resistant peptide produced by Ligilactobacillus salivarius subsp. salivarius CRL 1328).\nSeveral studies have indicated that the activity of bacteriocins is favored by low pH.\nThe inhibitory substances produced by vaginal [Lactobacillus](https://bliptext.com/articles/lactobacillus) is a primary factor in protecting the vaginal microbiota, with organic acids, bacteriocins, and hydrogen peroxide.\nThese act synergistically against infection by pathogens.\nNot all Lactobacillus spp.\nand not all strains within one Lactobacillus species exhibit all 3 mechanisms.\nLactobacillus species differ in premenopausal women, i.e. [L. crispatus](https://bliptext.com/articles/lactobacillus-crispatus), [L. jensenii](https://bliptext.com/articles/lactobacillus-jensenii), [L. iners](https://bliptext.com/articles/lactobacillus-iners), [L. gasseri](https://bliptext.com/articles/lactobacillus-gasseri) (and possibly [L. vaginalis](https://bliptext.com/articles/lactobacillus-vaginalis)), as assessed through cultivation-dependent and cultivation-independent techniques.\nVaginal lactobacilli have been shown to display a pronounced vaginotropism, and their pili act as ligands for attachment to receptors of vaginal epithelial cells.\nThe limited number of Lactobacillus spp.\nfound in the human vagina is remarkable, which leads to the possibility that there are host factors that select for specific organisms, that these species\nhave unusual characteristics that allow them to successfully colonize the vagina, or both\n. However, the vaginotropism, does not only apply to this selected group of lactobacilli\nthat stand for a healthy vagina, but also for the bacterial species associated with BV.\nThe microbiota detected in the human genital and gut econiche do not appear to grow outside their\nhost and probably are likely to rely on the close contact between parents and their children for transmission, e.g. mother to neonate transmission of genital microflora, most probably also with gut microflora homogenously distributed over the baby's body including skin, the oral cavity, nasopharynx, and feces.\n\n# Bacteria vaginosis\n[Bacterial vaginosis](https://bliptext.com/articles/bacterial-vaginosis) (BV) is associated with the presence of [Gardnerella vaginalis](https://bliptext.com/articles/gardnerella-vaginalis) and [Peptostreptococcus anaerobius](https://bliptext.com/articles/peptostreptococcus-anaerobius) and a decrease in the number of [Lactobacillus](https://bliptext.com/articles/lactobacillus) species that comprise the healthy vaginal microbiota.\nBV is characterized by overgrowth of opportunistic bacteria and a decrease in Lactobacillus species.\nBV can present itself as symptomatic or asymptomatic.\nSymptoms include vaginal malodor, increased vaginal pH, and vaginal itching.\nThere is no one known cause as to why BV occurs but it is typically associated with abnormal vaginal discharge (Coudray & Madhivanan, 2020).\nTo diagnose BV in a clinical setting, an Amsel's criteria is used.\nThis means that a patient must have an increased homogeneous thin vaginal discharge, pH secretion higher than 4.5, amine odor when secretions are exposed to hydroxide 10% solution, or clue cells visible on a wet mount.\nAnother way to diagnose BV that is less often used in a clinical setting is a Nugent score.\nTo obtain a Nugent score, gram stain techniques are carried out and it characterizes the bacterial morphology on a scale.\nA score greater than 7 is associated with BV, 4-6 is an intermediate abnormality, and 0-3 is normal.\nTypically, only women with symptoms receive treatment.\nTreatment include antibiotics, specifically metronidazole and clindamycin (Hay, 2010).\nStudies have shown a correlation between vaginal microbiota and BV development through 16S RNA sequencing.\nCommunity state types (CSTs) are used to identify variation between a healthy vaginal microbiota and vaginal microbiota of someone with BV.\nMost CSTs in a healthy vaginal microbiome consist of different species of Lactobacillus. Studies found that L.iners is the dominant species in BV and L.crispatus is the dominant species in healthy vaginal microbiomes.\n\n# Other microbiota\nHealthy, normal vaginal microbiota that is dominated by lactobacilli may differ among some ethnic groups.\n[Non-pathogenic](https://bliptext.com/articles/nonpathogenic-organisms) vaginal species are part of the normal microbiota of some women.\nSeveral studies have demonstrated that a significant proportion (7–33%) of healthy asymptomatic women (especially black and Hispanic women) lack appreciable numbers of Lactobacillus species in the vagina, and instead have a vaginal microbiota that consist of other lactic acid-producing bacteria, i.e. species from the genera [Atopobium](https://bliptext.com/articles/atopobium), [Leptotrichia](https://bliptext.com/articles/leptotrichia-buccalis), [Leuconostoc](https://bliptext.com/articles/leuconostoc), [Megasphaera](https://bliptext.com/articles/megasphaera), [Pediococcus](https://bliptext.com/articles/pediococcus), [Streptococcus](https://bliptext.com/articles/streptococcus) and [Weissella](https://bliptext.com/articles/weissella), All ethnic populations have vaginal microflora communities containing lactic acid producing bacteria.\nThis implies that not all communities may be equally resilient, so that if the resilience of a vaginal community is low then transitory changes in the structure of these communities may occur more readily in response to disturbances of various kinds, including [menses](https://bliptext.com/articles/menses), sexual intercourse, douching and contraceptive practices.\nThese differences in the structure and composition of microbial communities may underlie well-known differences in the susceptibility of women in these racial groups to BV and various vaginal infections.\nThough vaginal microflora may be disturbed, and lactic acid is produced by other species, vaginal pH and acid production establish normal vaginal microbiota.\nThe pH further decreases during pregnancy.\n# [Gram stain of lactobacilli and squamous epithelial cells in vaginal swab | upload.wikimedia.org/wikipedia/commons/a/af/Lactobacilli///%28Gram///stain%29.jpg]\n\n# Other vaginal bacterial species\nOther bacterial species are frequently found in the vagina, such as the Gram positive cocci: [Atopobium vaginae](https://bliptext.com/articles/atopobium-vaginae), Peptostreptococcus spp., Staphylococcus spp., Streptococcus spp., and Bacteroides spp., Fusobacterium spp., [Gardnerella vaginalis](https://bliptext.com/articles/gardnerella-vaginalis), [Mobiluncus](https://bliptext.com/articles/mobiluncus), Prevotella spp., and [Gram-negative enteric organisms](https://bliptext.com/articles/gram-negative-bacteria), such as [Escherichia coli](https://bliptext.com/articles/escherichia-coli).\n[Mycoplasma](https://bliptext.com/articles/mycoplasma-genitalium) and [Ureaplasma](https://bliptext.com/articles/ureaplasma-urealyticum) are frequently found in the vagina.\nSome of the obligate and facultative anaerobic bacteria are associated with BV.\n[Neisseria gonorrhoeae](https://bliptext.com/articles/neisseria-gonorrhoeae) is found in the vagina and is considered a [pathogen](https://bliptext.com/articles/pathogen) that is sexually transmitted.\n# [Gram stain of a vaginal swab showing gonococci (in pairs - arrow) inside polymorphonuclear granulocytes | upload.wikimedia.org/wikipedia/commons/0/04/Neisseria///gonorrhoeae///and///pus///cells///in///a///vaginal///swab///%28Gram///stain%29.jpg]\n\n# Pregnancy\nThe effect of [tampon](https://bliptext.com/articles/tampon) use on vaginal flora is debated, but application of [tampon](https://bliptext.com/articles/tampon)s appears not to significantly modify the balance of bacterial presence.\nPregnancy alters the microbiota with a reduction in species/genus diversity.\n\n# Disease prevention\nA healthy vaginal microbiome aids in the prevention of bacterial vaginosis, [yeast infections](https://bliptext.com/articles/vaginal-yeast-infection) and other possible problems by maintaining an acidic pH (< 4.5) that is unfavourable for the growth of common pathogens, such as [Gardnerella vaginalis](https://bliptext.com/articles/gardnerella-vaginalis).\nThe lactobacilli present in a healthy vaginal microbiome also occupy the [ecological niche](https://bliptext.com/articles/ecological-niche) that would otherwise be available for exploitation by pathogenic organisms.\nHowever, harmful bacteria or an imbalance in bacteria can lead to infection.\nThere are many factors that contribute to the composition of vaginal microbiota including stress, age, lifestyle, diet, gut microbiota, antibiotics, probiotics, and vaginal infections.\nLifestyle can impact microbiota by means of personal hygiene.\nResearch suggests that vaginal douching is associated with increased risk of BV.\nIt also shows that sexual practices that include multiple sexual partners can increase BV or throw off stable microbiota composition.\nSmoking and alcohol consumption can also increase likelihood of BV development because it indirectly impacts the metabolite production profile.\nThere is also research supporting the idea that increased stress levels can have an impact on the balance of vaginal lactobacilli by elevating cortisol levels, reducing vaginal glycogen, lowering lactobacilli, elevating vaginal pH, and increasing proinflammatory response.\nIt is becoming more commonly known how our diets can impact our gut microbiota, but it can have the same impact on vaginal microbiota.\nResearch shows that diets rich in nutrients with low glycemic index and lower fat intake may be associated with a decreased chance of getting BV.\n# [Vaginal squamous cell with normal vaginal flora versus bacterial vaginosis on Pap stain. Normal vaginal flora (left) is predominantly rod-shaped Lactobacilli, whereas in bacterial vaginosis (right) there is an overgrowth of bacteria, which can be of various species. | upload.wikimedia.org/wikipedia/commons/f/f5/Normal///vaginal///flora///versus///bacterial///vaginosis///on///Pap///stain.jpg]\n\n# Research\nInvestigations have found that the presence of lactobacilli in the vagina is associated with a lower incidence of sexually transmitted infections.","current_revision":null,"created_by":"kACnuQmH5k9Nr5VNVEpVeg7XpvUmMctD","created_at":"2025-01-26T09:35:39.168Z","updated_at":"2025-01-26T09:35:39.168Z","search_vector":"'flora':2 'vagin':1","search_content":" \n \n\n# \n**Vaginal flora**, **[vagina](https://bliptext.com/articles/vagina)l microbiota** or **[vagina](https://bliptext.com/articles/vagina)l microbiome** are the [microorganisms](https://bliptext.com/articles/microorganisms) that colonize the [vagina](https://bliptext.com/articles/vagina).\nThey were discovered by the German gynecologist [Albert Döderlein](https://bliptext.com/articles/albert-d-derlein) in 1892 and are part of the overall [human flora](https://bliptext.com/articles/human-flora).\nThe amount and type of bacteria present have significant implications for an individual's overall health.\nThe primary colonizing bacteria of a healthy individual are of the genus [Lactobacillus](https://bliptext.com/articles/lactobacillus), such as [L. crispatus](https://bliptext.com/articles/lactobacillus-crispatus), and the [lactic acid](https://bliptext.com/articles/lactic-acid) they produce is thought to protect against infection by pathogenic species.\n# [Lactobacilli and a vaginal squamous cell | upload.wikimedia.org/wikipedia/commons/7/7d/Lactobacillus///sp///01.png]\n\n# Lactobacilli\nThe primary colonizing bacteria of a healthy individual are of the genus [Lactobacillus](https://bliptext.com/articles/lactobacillus) (90–95%), the most common being [L. crispatus](https://bliptext.com/articles/lactobacillus-crispatus), [L. iners](https://bliptext.com/articles/lactobacillus-iners), [L. jensenii](https://bliptext.com/articles/lactobacillus-jensenii), and [L. gasseri](https://bliptext.com/articles/lactobacillus-gasseri).\nSince the first description of lactobacilli by Döderlein, lactobacilli have been generally considered the gatekeepers of the vaginal ecosystem.\nLactobacilli have been shown to inhibit in vitro growth of pathogenic microorganisms, e.g. [Bacteroides fragilis](https://bliptext.com/articles/bacteroides-fragilis), [Escherichia coli](https://bliptext.com/articles/escherichia-coli), [Gardnerella vaginalis](https://bliptext.com/articles/gardnerella-vaginalis), Mobiluncus spp., [Neisseria gonorrhoeae](https://bliptext.com/articles/neisseria-gonorrhoeae), [Peptostreptococcus anaerobius](https://bliptext.com/articles/peptostreptococcus-anaerobius), [Prevotella bivia](https://bliptext.com/articles/prevotella-bivia) and [Staphylococcus aureus](https://bliptext.com/articles/staphylococcus-aureus).\nIt is generally accepted that this is achieved mainly through the action of lactic acid.\nMoreover, lactobacilli normally help to prevent long-term colonization of the vagina by adhering to vaginal epithelial cells.\nThis usually reduces pathogens from infecting to the [vaginal epithelium](https://bliptext.com/articles/vaginal-epithelium).\nNext to lactic acid production and competition for adherence, other antagonistic mechanisms include [hydrogen peroxide](https://bliptext.com/articles/hydrogen-peroxide) (a broad-spectrum antimicrobial) and [bacteriocins](https://bliptext.com/articles/bacteriocin) (target-specific antimicrobials) production.\n\n## pH and lactic acid\nLow pH is generally accepted to be the main mechanism controlling the composition of the vaginal microflora.\nAlthough the lactic acid produced by lactobacilli contributes to the vaginal acidity, it is still not proven to be the primary source of low vaginal pH, but the fact remains that most lactobacilli thrive best at a pH 2 O 2 ) is a proposed mechanism for bacterial antagonism in vitro, inhibiting growth of microorganisms via direct interaction or via human myeloperoxidase.\nHowever, in vivo, the role of peroxide is uncertain.\nUnder optimal anaerobic growth conditions, physiological concentrations of lactic acid inactivated the [BV-associated pathogens](https://bliptext.com/articles/bacterial-vaginosis) without affecting the vaginal lactobacilli.\nAlthough the hydrogen peroxide production of lactobacilli has been considered as an important antimicrobial component, contributing to the colonization resistance provided by lactobacilli, and although there seems to be a link between H 2 O 2 -producing lactobacilli and normal vaginal microflora, recent data do not support this role for H 2 O 2 .\nExperimentally, hydrogen peroxide-producing lactobacilli have been shown to inactivate [HIV-1](https://bliptext.com/articles/hiv), [herpes simplex virus type 2](https://bliptext.com/articles/herpes-simplex-virus) (HSV-2), [Trichomonas vaginalis](https://bliptext.com/articles/trichomonas-vaginalis), [G. vaginalis](https://bliptext.com/articles/gardnerella-vaginalis), [P. bivia](https://bliptext.com/articles/prevotella-bivia) and [E. coli](https://bliptext.com/articles/escherichia-coli).\nO'Hanlon and Baeten found that 96% of [Lactobacillus](https://bliptext.com/articles/lactobacillus) species from a healthy vaginal ecosystem produced H 2 O 2 ([L. jensenii](https://bliptext.com/articles/lactobacillus-jensenii) and [L. vaginalis](https://bliptext.com/articles/lactobacillus-vaginalis) produce the highest levels of H 2 O 2 ), whereas only 6% of the lactobacilli recovered from women with BV produced H 2 O 2 .\nIn agreement with this, [L. iners](https://bliptext.com/articles/lactobacillus-iners), most frequently associated with disturbed vaginal microflora, is a poor producer of H 2 O 2 .\nVaginal colonization by H 2 O 2 -producing lactobacilli has been associated with a decrease in the occurrence of [bacterial vaginosis](https://bliptext.com/articles/bacterial-vaginosis) (BV).\nHowever, more recently O'Hanlon et al. demonstrated that cervicovaginal fluid and semen have a significant H 2 O 2 -blocking activity and they later demonstrated that physiological concentrations of H 2 O 2 below 100 μM fail to inactivate any of the 17 tested BV-associated bacteria, e.g. [A. vaginae](https://bliptext.com/articles/atopobium-vaginae), [G. vaginalis](https://bliptext.com/articles/gardnerella-vaginalis), Mobiluncus spp., [P. bivia](https://bliptext.com/articles/prevotella-bivia), [P. corporis](https://bliptext.com/articles/prevotella), [Mycoplasma hominis](https://bliptext.com/articles/mycoplasma-hominis), even in the presence of human [myeloperoxidase](https://bliptext.com/articles/myeloperoxidase), known to increase the microbicidal activity of H 2 O 2 .\nOnly supraphysiologic concentrations of exogenous H 2 O 2 (0.34% w/v, 100 mM) were sufficient to inactivate BV-associated bacteria at which concentration it more potently inactivated vaginal lactobacilli ([L. crispatus](https://bliptext.com/articles/lactobacillus-crispatus), [L. gasseri](https://bliptext.com/articles/lactobacillus-gasseri), [L. iners](https://bliptext.com/articles/lactobacillus-iners) and [L. jensenii](https://bliptext.com/articles/lactobacillus-jensenii)).\nA concentration of 100 mM H 2 O 2 is approximately 50-fold higher than lactobacilli are capable of producing even under optimal aerobic, low-antioxidant conditions, and approximately 5,000-fold higher than the estimated H 2 O 2 concentration in vivo. Even more remarkable, the addition of only 1% vaginal fluid blocked the microbicidal activity of 1 M H 2 O 2 .\nPossible explanations may be that cervicovaginal fluid and semen contain proteins, glycoproteins, polysaccharides, lipids, and other molecules with the potential to react with and inactivate H 2 O 2 .\nIn addition, the vagina is hypoxic most of the time, whereas lactobacilli require oxygen to produce hydrogen peroxide.\nIt is also remarkable that catalase, which provides bacteria protection against toxic H 2 O 2 , is absent in lactobacilli, and as such they would be unprotected against their own H 2 O 2 production.\nConsequently, hydrogen peroxide production may not be the major mechanism of defense.\n\n## Bacteriocins\nVaginal lactobacilli produce antimicrobial peptides, i.e. bacteriocins such as lactocin 160 and crispasin.\nwith inhibitory activity ranging from narrow (closely related Lactobacillus species) to broad (diverse groups of bacteria, including [G. vaginalis](https://bliptext.com/articles/gardnerella-vaginalis) and [P. bivia](https://bliptext.com/articles/prevotella-bivia)), and bacteriocin-like substances, with a broader spectrum of activity than bacteriocins (e.g. a heat-resistant peptide produced by Ligilactobacillus salivarius subsp. salivarius CRL 1328).\nSeveral studies have indicated that the activity of bacteriocins is favored by low pH.\nThe inhibitory substances produced by vaginal [Lactobacillus](https://bliptext.com/articles/lactobacillus) is a primary factor in protecting the vaginal microbiota, with organic acids, bacteriocins, and hydrogen peroxide.\nThese act synergistically against infection by pathogens.\nNot all Lactobacillus spp.\nand not all strains within one Lactobacillus species exhibit all 3 mechanisms.\nLactobacillus species differ in premenopausal women, i.e. [L. crispatus](https://bliptext.com/articles/lactobacillus-crispatus), [L. jensenii](https://bliptext.com/articles/lactobacillus-jensenii), [L. iners](https://bliptext.com/articles/lactobacillus-iners), [L. gasseri](https://bliptext.com/articles/lactobacillus-gasseri) (and possibly [L. vaginalis](https://bliptext.com/articles/lactobacillus-vaginalis)), as assessed through cultivation-dependent and cultivation-independent techniques.\nVaginal lactobacilli have been shown to display a pronounced vaginotropism, and their pili act as ligands for attachment to receptors of vaginal epithelial cells.\nThe limited number of Lactobacillus spp.\nfound in the human vagina is remarkable, which leads to the possibility that there are host factors that select for specific organisms, that these species\nhave unusual characteristics that allow them to successfully colonize the vagina, or both\n. However, the vaginotropism, does not only apply to this selected group of lactobacilli\nthat stand for a healthy vagina, but also for the bacterial species associated with BV.\nThe microbiota detected in the human genital and gut econiche do not appear to grow outside their\nhost and probably are likely to rely on the close contact between parents and their children for transmission, e.g. mother to neonate transmission of genital microflora, most probably also with gut microflora homogenously distributed over the baby's body including skin, the oral cavity, nasopharynx, and feces.\n\n# Bacteria vaginosis\n[Bacterial vaginosis](https://bliptext.com/articles/bacterial-vaginosis) (BV) is associated with the presence of [Gardnerella vaginalis](https://bliptext.com/articles/gardnerella-vaginalis) and [Peptostreptococcus anaerobius](https://bliptext.com/articles/peptostreptococcus-anaerobius) and a decrease in the number of [Lactobacillus](https://bliptext.com/articles/lactobacillus) species that comprise the healthy vaginal microbiota.\nBV is characterized by overgrowth of opportunistic bacteria and a decrease in Lactobacillus species.\nBV can present itself as symptomatic or asymptomatic.\nSymptoms include vaginal malodor, increased vaginal pH, and vaginal itching.\nThere is no one known cause as to why BV occurs but it is typically associated with abnormal vaginal discharge (Coudray & Madhivanan, 2020).\nTo diagnose BV in a clinical setting, an Amsel's criteria is used.\nThis means that a patient must have an increased homogeneous thin vaginal discharge, pH secretion higher than 4.5, amine odor when secretions are exposed to hydroxide 10% solution, or clue cells visible on a wet mount.\nAnother way to diagnose BV that is less often used in a clinical setting is a Nugent score.\nTo obtain a Nugent score, gram stain techniques are carried out and it characterizes the bacterial morphology on a scale.\nA score greater than 7 is associated with BV, 4-6 is an intermediate abnormality, and 0-3 is normal.\nTypically, only women with symptoms receive treatment.\nTreatment include antibiotics, specifically metronidazole and clindamycin (Hay, 2010).\nStudies have shown a correlation between vaginal microbiota and BV development through 16S RNA sequencing.\nCommunity state types (CSTs) are used to identify variation between a healthy vaginal microbiota and vaginal microbiota of someone with BV.\nMost CSTs in a healthy vaginal microbiome consist of different species of Lactobacillus. Studies found that L.iners is the dominant species in BV and L.crispatus is the dominant species in healthy vaginal microbiomes.\n\n# Other microbiota\nHealthy, normal vaginal microbiota that is dominated by lactobacilli may differ among some ethnic groups.\n[Non-pathogenic](https://bliptext.com/articles/nonpathogenic-organisms) vaginal species are part of the normal microbiota of some women.\nSeveral studies have demonstrated that a significant proportion (7–33%) of healthy asymptomatic women (especially black and Hispanic women) lack appreciable numbers of Lactobacillus species in the vagina, and instead have a vaginal microbiota that consist of other lactic acid-producing bacteria, i.e. species from the genera [Atopobium](https://bliptext.com/articles/atopobium), [Leptotrichia](https://bliptext.com/articles/leptotrichia-buccalis), [Leuconostoc](https://bliptext.com/articles/leuconostoc), [Megasphaera](https://bliptext.com/articles/megasphaera), [Pediococcus](https://bliptext.com/articles/pediococcus), [Streptococcus](https://bliptext.com/articles/streptococcus) and [Weissella](https://bliptext.com/articles/weissella), All ethnic populations have vaginal microflora communities containing lactic acid producing bacteria.\nThis implies that not all communities may be equally resilient, so that if the resilience of a vaginal community is low then transitory changes in the structure of these communities may occur more readily in response to disturbances of various kinds, including [menses](https://bliptext.com/articles/menses), sexual intercourse, douching and contraceptive practices.\nThese differences in the structure and composition of microbial communities may underlie well-known differences in the susceptibility of women in these racial groups to BV and various vaginal infections.\nThough vaginal microflora may be disturbed, and lactic acid is produced by other species, vaginal pH and acid production establish normal vaginal microbiota.\nThe pH further decreases during pregnancy.\n# [Gram stain of lactobacilli and squamous epithelial cells in vaginal swab | upload.wikimedia.org/wikipedia/commons/a/af/Lactobacilli///%28Gram///stain%29.jpg]\n\n# Other vaginal bacterial species\nOther bacterial species are frequently found in the vagina, such as the Gram positive cocci: [Atopobium vaginae](https://bliptext.com/articles/atopobium-vaginae), Peptostreptococcus spp., Staphylococcus spp., Streptococcus spp., and Bacteroides spp., Fusobacterium spp., [Gardnerella vaginalis](https://bliptext.com/articles/gardnerella-vaginalis), [Mobiluncus](https://bliptext.com/articles/mobiluncus), Prevotella spp., and [Gram-negative enteric organisms](https://bliptext.com/articles/gram-negative-bacteria), such as [Escherichia coli](https://bliptext.com/articles/escherichia-coli).\n[Mycoplasma](https://bliptext.com/articles/mycoplasma-genitalium) and [Ureaplasma](https://bliptext.com/articles/ureaplasma-urealyticum) are frequently found in the vagina.\nSome of the obligate and facultative anaerobic bacteria are associated with BV.\n[Neisseria gonorrhoeae](https://bliptext.com/articles/neisseria-gonorrhoeae) is found in the vagina and is considered a [pathogen](https://bliptext.com/articles/pathogen) that is sexually transmitted.\n# [Gram stain of a vaginal swab showing gonococci (in pairs - arrow) inside polymorphonuclear granulocytes | upload.wikimedia.org/wikipedia/commons/0/04/Neisseria///gonorrhoeae///and///pus///cells///in///a///vaginal///swab///%28Gram///stain%29.jpg]\n\n# Pregnancy\nThe effect of [tampon](https://bliptext.com/articles/tampon) use on vaginal flora is debated, but application of [tampon](https://bliptext.com/articles/tampon)s appears not to significantly modify the balance of bacterial presence.\nPregnancy alters the microbiota with a reduction in species/genus diversity.\n\n# Disease prevention\nA healthy vaginal microbiome aids in the prevention of bacterial vaginosis, [yeast infections](https://bliptext.com/articles/vaginal-yeast-infection) and other possible problems by maintaining an acidic pH (< 4.5) that is unfavourable for the growth of common pathogens, such as [Gardnerella vaginalis](https://bliptext.com/articles/gardnerella-vaginalis).\nThe lactobacilli present in a healthy vaginal microbiome also occupy the [ecological niche](https://bliptext.com/articles/ecological-niche) that would otherwise be available for exploitation by pathogenic organisms.\nHowever, harmful bacteria or an imbalance in bacteria can lead to infection.\nThere are many factors that contribute to the composition of vaginal microbiota including stress, age, lifestyle, diet, gut microbiota, antibiotics, probiotics, and vaginal infections.\nLifestyle can impact microbiota by means of personal hygiene.\nResearch suggests that vaginal douching is associated with increased risk of BV.\nIt also shows that sexual practices that include multiple sexual partners can increase BV or throw off stable microbiota composition.\nSmoking and alcohol consumption can also increase likelihood of BV development because it indirectly impacts the metabolite production profile.\nThere is also research supporting the idea that increased stress levels can have an impact on the balance of vaginal lactobacilli by elevating cortisol levels, reducing vaginal glycogen, lowering lactobacilli, elevating vaginal pH, and increasing proinflammatory response.\nIt is becoming more commonly known how our diets can impact our gut microbiota, but it can have the same impact on vaginal microbiota.\nResearch shows that diets rich in nutrients with low glycemic index and lower fat intake may be associated with a decreased chance of getting BV.\n# [Vaginal squamous cell with normal vaginal flora versus bacterial vaginosis on Pap stain. Normal vaginal flora (left) is predominantly rod-shaped Lactobacilli, whereas in bacterial vaginosis (right) there is an overgrowth of bacteria, which can be of various species. | upload.wikimedia.org/wikipedia/commons/f/f5/Normal///vaginal///flora///versus///bacterial///vaginosis///on///Pap///stain.jpg]\n\n# Research\nInvestigations have found that the presence of lactobacilli in the vagina is associated with a lower incidence of sexually transmitted infections.","revisionCount":0},"hasMore":false,"nextCursor":null}

History