Haven’t heard of the skin microbiome? You will. In this interview, Dr. Cassandra Quave, Assistant Professor of Dermatology and Human Health at Emory University and Medline consultant, explains the impact of the skin microbiome and what’s being done to better understand it.
What is the skin microbiome?
When you visualize the microbiome as an ecosystem, the skin has different environmental characteristics depending on its location on the body. Think of the forearm as a human dry desert, and areas with skinfolds (i.e., the armpit or groin) as a hot, wet jungle. These environments differ in pH, humidity, temperature, light exposure and even salinity, which greatly impacts the types of microbes that flourish there. Other factors that can influence the composition of the skin microbiome include a host’s gender, genotype, immune status and cosmetic use.
Most microbes found on or in the body are not harmful and very few are pathogenic. However, opportunities exist for them to become pathogenic. For example, Propionibacterium acnes (acne) and Staphylococcus epidermidis are both part of the normal skin microbiome. But if either attaches to a wrong habitat (i.e., an implanted medical device such as an IV catheter or joint replacement), it can wreak problems.
We can distinguish between an infection and normal skin microflora. An inflammatory skin disease such as eczema is usually associated with heavy microbial load. If you look at the microbial makeup of an eczema flare site, it’s densely populated with Staphylococcus aureus. However, we still don’t know what kick-started the problem—the disease, problems or mutations within the host, or bacteria.
Why the skin microbiome is so important to skin and wound care specialists:
The microbiome plays a role in the health of the skin environment of patients. The wound bed microbiome is an area of medical relevance. Chronic wounds don’t heal in part because of the presence of certain microbes, such as Pseudomonas or Staphylococcus. They can prevent epithelization or wound healing in the wound bed.
Other microbes that aren’t affiliated with the wound but may be linked to inflammatory skin diseases can cause discomfort in patients. The itch from eczema is a prime example.
The microbiome of the wound bed differs from normal skin in that it tends to be a dysbiotic environment, where a few species predominate and can cause a lot of harm. For therapeutic development, we’re always thinking about how we can weaken their hold in that environment. How do we create a shift in that ecosystem that could facilitate better wound healing?
Historically, we’ve been limited in our ability to grow and culture microbes in the laboratory. The Human Microbiome Project is using genome sequencing to evaluate the makeup of different microbes in different body sites.