Exposure of Exiguobacterium spp. to dengue vector, Aedes aegypti reduces growth and reproductive fitness

Background Aedes aegypti is a major insect vector because it transmits dreadful viruses as adults that cause disease in humans and other vertebrates. The use of mosquito’s microbiota has shown great potential impacts on vector control and mosquito reproductive competence. The present study aimed to examine the resident bacteria of mosquitoes which are used as a potent range to reduce the A. aegypti fitness. Isolated resident-bacterial strains from blood-fed Aedes species were characterized using gene sequencing and phylogenetic analysis, to assess the inhabitant bacterial strains survival rate in A. aegypti midgut, instar developmental duration, malformation and reproductive competence. Results The genetic distinctiveness of isolated bacterial strains belong to the genus Exiguobacterium spp. and further non-redundant nucleotide database search revealed that the species of effective strains were E. aestuarii (MN629357) and E. profundum (MN625885). Exposure of the freshly hatched larvae with these bacteria cell densities extended the developmental duration. For instance, exposure of A. aegypti larva with 0.42 × 108, 0.84 × 108 and 1.68 × 108 cells/mL of E. aestuarii extended the total developmental duration to 11.41, 14.29 and 14.78 days, respectively. It also reduced the fecundity and hatchability of A. aegypti female, with exposure to these bacteria, from 1033.33 eggs/10 females in the control series to 656.67 eggs/10 females. Conclusions These present findings indicate that the resident-bacterial strains from blood-fed mosquito not only extend the larval durations but also rendered the A. aegypti females sterile to various extents.