The role of the fungal mycobiome in women's health

By Pooja Toshniwal PahariaReviewed by Benedette Cuffari, M.Sc.Mar 15 2023

In a recent review published in the Journal of Fungi, researchers in New York, USA, review existing data on the association between human mycobiota and female health.

Study: The Role of the Mycobiome in Women’s Health. Image Credit: Kateryna Kon / Shutterstock.com

Bacteria and fungal infections

Previous studies have reported considerable diversity in the human mycobiome. Nevertheless, an improved understanding of the mycobiome would aid in elucidating the pathophysiology of and immune responses to fungal infections and, as a result, the development antimycotic therapies.

Fungal and bacterial microbiota are interlinked, as demonstrated by the ability of bacteria to prevent commensal Candida organisms from causing disease by inhibiting yeast-hyphal conversion and increasing the integrity of the epithelium. Additional research is needed to characterize the fungal microbiome in health and infection, as well as improve disease states by restoring the microbial imbalance.

In the present review, researchers discuss the human female mycobiome and the impact of mycobiome dysbiosis on female health.

The fungal microbiome of women

The oral mycobiome is dominated by Candida, Cladosporium, Aureobasidium, Saccharomycetales, Aspergillus, Fusarium, Cryptococcus, Pichia, and Malassezia, whereas human breast milk is dominated by Candida, Cryptococcus, and Saccharomyces.

The most abundant fungal microbes in the human gut include Candida, Saccharomyces, Malassezia, and Cladosporium. Comparatively, Candida, 70% of which are Candida albicans, Saccharomycetales, Davidiellaceae, Cadosporium, and Pichia dominate the vaginal mycobiome.

Female skin mycobiome is abundant in Malassezia, Candida, Cladosporium, Fusarium, and Cryptococcus. Among Candida species, C. albicans is the most abundant in women.

The fungal microbiome varies considerably by age, gender, physical exercise, routine activities, nutrition, infections, and medications, particularly antibiotic and antifungal drugs. Human immunodeficiency virus (HIV) infections and smokeless tobacco consumption significantly reduce fungal microbial diversity and richness, thereby resulting in Pichia dominance, which can lead to oral cancers.

Other factors including the reduced flow of saliva, pH, and denture use are linked to elevated Candida counts. Increased abundance of C. dubliniensis and C. glabrata has been observed in the elderly with a low body mass index (BMI) and is likely associated with immunosuppression and enhanced susceptibility to Candida infections in older individuals.

In postpartum females, increased abundance of Geotrichum, Stachybotrys, Leucosporidium, Talaromyces, Wallemia, Acremonium, Septoria, Eupenicillium, Coniosporium, Zymoseptoria, Mycosphaerella, and Phialophora has been observed. Individuals with greater educational attainment, as well as those consuming more vegetables and fruits, often exhibit lower C. parapsilosis counts. Malassezia is reportedly more dominant in the skin of women than men.

Significance of mycobiota dysbiosis on female health

Elevated counts of Exophiala and Filobasidium have been reported among intrauterine adhesion (IUA) patients, with reduced fibrosis and inflammation in vagina tissues exposed to C. parapsilosis. Vaginal mycobiome dysbiosis also destroys the bacterial microbiome of the vagina.

Women suffering from recurrent vaginal candidiasis (RVC) exhibit increased C. albicans abundance and reduced abundance of S. cerevisiae in the vagina than their healthy counterparts.

Intestinal mycobiota imbalance is related to Crohn’s disease, bacterial imbalance, and cirrhosis. More specifically, elevated Malassezia restricta, Ascomycota, and Basidiomycota counts have been reported in Crohn’s disease.

In the cutaneous lesions of atopic dermatitis, lower Malassezia counts and increased filamentous fungal organisms’ have been observed. Comparatively, increased Malassezia abundance is related to pancreatic and colorectal cancer development. Cutaneous fungal microbes such as Candida and Malassezia produce robust immune responses and sensitize the skin at lesional sites.

Increased Schizophyllum abundance benefits the host, as the fungi possess antimicrobial and anticancer properties. Fungi like Candida albicans are key immunological regulators and are critically involved during eubiotic mechanisms in immunological priming.

Signal cascades are triggered, wherein dendritic cells recognize fungi and induce helper T lymphocyte responses and anti-fungal immunoglobulin G (IgG) titers to pro-inflammatory cytokines. Fungal microbes also secrete metabolites like candidalysin that function as cytotoxins to promote antimycotic immune responses and immunological cascades.

Mycobiome changes also alter bacterial microbiota, thereby influencing essential metabolites in the human body, including organic acids, short-chain fatty acids, butyrate, succinate, and taurine.  

Fungal metabolites, categorized as non-ribosomal peptide synthases, polyketide synthases, steroids, terpenoids, and fatty acid derivatives have been implicated in Alzheimer’s disease, cancers, and various metabolic disorders. For example, N-acetyl-L-glutamic acid results in hypotension.

Alterations in the fungal microbiome affect the metabolism of proteins, carbohydrates, and lipids. This can lead to the production of multiple secondary metabolite molecules, such as sugars, toxins, and acids.

Conclusions

The fungal microbiome of women is significantly associated with the bacterial microbiome and is critically involved in disease pathophysiology, immunological responses, and overall health.