Most people know atopic dermatitis by its common name, eczema—that dry, flaky skin that itches incessantly. Along with the scratching comes frequent skin infections, often with Staphylococcus aureus.
S. aureus skin infections can look like pimples, boils, or red, swollen, and painful skin eruptions. It can mutate in response to constant treatment with different antibiotics to become MRSA (methicillin resistant Staphylococcus aureus), a potentially life-threatening bacterial infection.
Relief from infections may come from a soothing moisturizer, but not just any lotion.
A team led by Dr. Teruaki Nakatsuji and Dr. Richard L. Gallo, from the dermatology department at University of California, San Diego, has reported development of a moisturizer containing good bacteria collected from a patient's own skin. This good bacteria helps to protect against infections with disease-causing S. aureus bacteria. The researchers call their approach an "autologous microbiome transplant"—which literally means transplanting a person's own bacteria back to them.
About 20% of the population has atopic dermatitis at some point in their life, and 90% of them are younger than five years old when the condition first appears. About 50% of those cases can persist into adulthood, and people with atopic dermatitis are prone to hay fever and allergies, as well.
Open skin caused by scratching the dry, itchy patches increases the chance of skin infections in people with atopic dermatitis. Adding to that vulnerability, the researchers found that bacteria on normal human skin, like Staphylococcus epidermidis and Staphylococcus hominis, inhibit infection-causing S. aureus, but that these protective bacteria aren't found as frequently on the skin of people with atopic dermatitis. And because the good staphylococcal organisms aren't as plentiful on the patients' skin, S. aureus is found more abundantly there.
The good bacteria provide protection against the pathogenic S. aureus by secreting two types of antibiotic proteins that the researchers discovered killed off the disease-causing S. aureus. Some of the types of beneficial bacteria even suppressed the growth of MRSA, but they didn't inhibit the growth of other bacteria associated with healthy skin, such as Propionibacterium acnes, S. epidermidis, and Corynebacterium minutissimum.
The new treatment approach—using a person's own bacterial makeup administered as an autologous microbiome transplant—to prevent skin infections has been approved by the Food and Drug Administration. In addition to the five patients reported by the study team in the journal Science Translational Medicine, a clinical trial is underway to objectively determine the treatment's effectiveness.
In the clinical trial, Dr. Gallo (also cofounder of MatriSys Bio, who develops skin bacteriotherapy products) and his team will capture the bacteria on subjects' skin where eczema patches are present. They will then grow the good, protective bacteria in the lab and put them into a base moisturizer. The moisturizer containing bacteria will be applied to one of the subject's arms, and the moisturizer without bacteria will be applied to the other arm. The investigators will measure the amount of S. aureus growing on each arm. Based on their just-published study of five patients, they expect that the protective bacteria in the moisturizer will lower the numbers of pathogenic S. aureus on their arms.
Using a natural antibiotic produced by the skin microbiome is superior to current pharmaceutical approaches because the bacteriotherapy does not kill protective bacteria strains. Antibiotic resistance is not likely to occur because the bacteria therapy is attacking pathogens by multiple different ways at once.
Restoring the natural skin defenses by adjusting the microbiome in favor of pathogen-inhibiting bacteria may not only keep people with atopic dermatitis from developing tough S. aureus infections, it may be the start of personalizing preventative treatments. And it just might impact the rate of MRSA infections, as well.