Fungal Skin Infections

The Skin's Own Bacteria Help Keep Fungal Infections in Check

The evidence here is moderate, built on comparison studies of affected versus healthy skin rather than large clinical trials.

Fungal skin infections, including athlete's foot and ringworm, are usually caused by dermatophytes, a group of fungi that feed on keratin, the tough protein that makes up skin, hair, and nails.

The bacteria living alongside these fungi on the skin appear to shape how easily they take hold.

A less diverse fungal community shows up in active infection

A study comparing the skin microbiome of people with athlete's foot to healthy people found healthy skin hosted a more diverse fungal community overall.

One bacterium, Corynebacterium tuberculostearicum, was notably less abundant on infected skin compared with healthy skin, while the fungus responsible for the infection, Trichophyton rubrum, was far more abundant.

A separate study of ringworm on the scalp in children found a similar pattern in reverse. Healthy scalp skin hosted greater bacterial and fungal diversity than the skin directly affected by the infection.

Source: Characterization of Skin Microbiome in Tinea Pedis

One specific bacterium directly interferes with the fungus

Research into the interaction between Pseudomonas aeruginosa, a bacterium commonly found on skin, and the dermatophyte fungi behind athlete's foot found the two actively compete with one another.

This competition has real clinical consequences. It can change how the infection actually presents, and it complicates lab testing, since the bacterium's presence can affect whether the fungus grows successfully in a diagnostic culture.

This is a useful, concrete example of the same general principle seen in the gut and elsewhere. One microbe's presence can measurably change how well another, harmful one manages to establish itself.

Source: Interaction between Pseudomonas aeruginosa and dermatophyte fungi: repercussions on the clinical course and microbiological diagnosis of tinea pedis

What this means for you

A fungal skin infection that spreads, doesn't improve with over-the-counter treatment, or affects the nails needs a doctor's assessment, since some cases need prescription antifungal treatment. In addition, the research above shows a more diverse skin bacterial and fungal community is linked to healthier skin, with specific bacteria shown to directly interfere with the fungi behind these infections. A varied, plant-rich diet supports the same kind of microbial diversity this research ties to a more resilient skin barrier. That's the same idea behind GutLab, everyday gut health starts with regularly feeding the microbiome a broad range of plant-rich ingredients.