Azitra, Ginkgo to develop microbial mosquito repellent

Beneficial microbes on our skin help to protect us against invasion by pathogens. Now a new project funded by the US Department of Defense could harness the skin’s microbiome to help soldiers in their battle against disease-carrying mosquitoes.

Azitra, a clinical dermatology company specializing in the skin microbiome, has joined with the biotech firm Ginkgo Bioworks, researchers at Florida International University, and the consultancy Lantham BioPharm Group on a $15 million research program funded by the Defense Advanced Research Projects Agency (DARPA). The project’s goal is to better protect members of the military operating in regions where mosquitoes carrying malaria and the Zika virus are endemic.

Currently available mosquito repellents like DEET (N,N-Diethyl-meta-toluamide) have to be reapplied every few hours, making them impractical for use in some military situations. Instead, the partners are studying how microbes can alter the skin-associated volatile compounds that attract mosquitoes. A product containing the microbes could provide protection from mosquito bites for up to two weeks, they say.

Researchers at Azitra are working with Ginkgo to engineer a strain of the skin bacteria Staphylococcus epidermidis so that it can reverse skin’s scent signals, says Travis Whitfill, the company’s Chief Science Officer. The bacteria would first eat up mosquito-attracting chemicals—compounds such as butyric acid. Then the microbes would produce mosquito-repelling volatile molecules. “They would make compounds similar to DEET, but that can be synthesized in bacteria and can be made continuously,” Whitfill says.

To test strains of engineered skin bacteria, Whitfill says researchers will use a tool called an olfactometer. A tester applies an ointment containing the bacteria to one arm and places it in a sleeve in a chamber with mosquitoes. The other arm, without the treatment, goes in a sleeve on the other side of the chamber. Then researchers count the difference in the numbers of mosquitoes attracted to each arm to measure the microbe’s effectiveness.