Bacteria: A novel source for potent mosquito feeding-deterrents.

Antibiotic and insecticidal bioactivities of the extracellular secondary metabolites produced by entomopathogenic bacteria belonging to genus have been identified; however, their novel applications such as mosquito feeding-deterrence have not been reported. Here, we show that a mixture of compounds isolated from in vitro cultures exhibits potent feeding-deterrent activity against three deadly mosquito vectors: , , and . We demonstrate that the deterrent active fraction isolated from replicate bacterial cultures is highly enriched in two compounds consistent with the previously described fabclavines, strongly suggesting that these are the molecular species responsible for feeding-deterrence. The mosquito feeding-deterrent activity in the putative fabclavine-rich fraction is comparable to or better than that of ,-diethyl-3-methylbenzamide (also known as DEET) or picaridin in side-by-side assays. These findings lay the groundwork for research into biologically derived, peptide-based, low-molecular weight compounds isolated from bacteria for exploitation as mosquito repellents and feeding-deterrents.