Discovery and mechanistic study of an <italic>Aedes aegypti</italic> lethalbacteria <italic>Chromobacterium</italic>

Abstract

Mosquitoes are arthropod vectors for many pathogens, and mosquito-borne diseases have become a major human health and economic concern in recent years. There is a large amount of microbiota in the mosquito gut, which may influence multiple aspects of vector physiology, including reproduction, metabolism, and immunity. In this study, we mainly focus on mosquito-microbiota interactions. Among the 18 strains isolated from the Aedes aegypti midgut, we found that Chromobacterium , a gut commensal bacteria, could significantly decrease mosquito longevity. We fed specimens a sugar source containing Chromobacterium at a concentration of 2.78×108 CFU/mL, which resulted in the rapid mortality of Aedes aegypti and Aedes albopictus . Moreover, the entomopathogenic activity of Chromobacterium was dose-dependent. Mechanistic investigations revealed that Chromobacterium could impair the mosquito midgut barrier and increase midgut permeability, leading to the enrichment of bacteria in the hemolymph, thus accelerating mosquito death. Additionally, a components study revealed that proteins secreted by Chromobacterium led to mosquito death. The mosquitocidal activity of Chromobacterium makes it a potential candidate for the development of enhanced mosquito control strategies.