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5-8-18

Bacteria therapy tested for common skin disease

Atopic dermatitis is the most common type of eczema. It can make skin dry and extremely itchy.

Rashes can form inside the elbows, behind the knees, and on the face, hands, and feet. Atopic dermatitis commonly starts in childhood. Children with a family history of allergy or asthma may be more likely to get atopic dermatitis. It often goes away during childhood, but some adults have it.

The cause of atopic dermatitis is unknown. Studies suggest that the skin microbiome-the community of bacteria and other microbes living on the skin-may play a key role. The skin of people with atopic dermatitis can have different types of bacteria than healthy skin. For example, the potentially harmful bacterium Staphylococcus aureus is more common on the skin of people with atopic dermatitis.

Animal and lab tests suggest that bacteria known as Roseomonas mucosa collected from healthy skin have qualities that may hold promise for treating people with atopic dermatitis. Based on these findings, investigators at NIH's National Institute of Allergy and Infectious Diseases (NIAID) designed an early stage clinical trial to test the safety and potential benefit of a treatment containing R. mucosa for people with atopic dermatitis. The research team, which was led by Dr. Ian A. Myles, published the results online on May 3 in JCI Insight.

The scientists used strains of R. mucosa from healthy skin to make the experimental treatment. They provided the bacterial therapy to 10 adults and 5 children with atopic dermatitis. The adults sprayed the treatment on the inside of their forearms near the elbow twice a week for six weeks. The children had the treatment applied to all affected skin areas twice weekly for 12 weeks and every other day for an additional four weeks. The participants still used their regular skin treatments if they needed to.

The researchers found that 6 of the 10 adults and 4 of the 5 children had more than 50 percent improvement in their atopic dermatitis. Some said they needed to use steroid lotion treatment less often. The scientists also noted decreases in the S. aureus population on the children's skin. None of the adults or children reported side effects. The researchers are continuing to study the five children who received treatment and are enrolling additional children for the study.

An analysis showed that R. mucosa from people with atopic dermatitis produced known skin irritants, while R. mucosa from healthy skin made beneficial chemicals. Lab experiments also found that a common type of preservative in skin products blocked the growth of R. mucosa collected from healthy skin. The relevance of this finding for people with atopic dermatitis needs to be further investigated.

"By applying bacteria from a healthy source to the skin of people with atopic dermatitis, we aim to alter the skin microbiome in a way that will relieve symptoms and free people from the burden of constant treatment," Myles says. "If future clinical studies demonstrate that this strategy is effective, we hope our work will lead to development of new, low-cost atopic dermatitis therapies that do not require daily application."

For further information on this and other health topics, visit the web site of the National Institute of Health at www.nih.gov.