Phlebotomus duboscqi gut microbiota dynamics in the context of Leishmania infection

BackgroundThe manipulation of the gut microbiota of disease vectors has emerged as a new approach to use in the integrated control of vector-borne diseases. For this purpose, a deep knowledge of the gut microbial communities of disease vectors is essential. However, while for some vectors, including mosquitoes, such characterization has been extensive, for others, including some sand fly species, there is limited data available. To our knowledge, to date, no study has documented the gut microbiome dynamics of Phlebotomus duboscqi sand flies over the entire time-period required for the maturation of a Leishmania infection. To address this limitation, here, we looked at the differences of the gut microbiome of laboratory-reared P. duboscqi sand flies both before, and after infection with Leishmania major parasites, with the necessary temporal resolution to understand the dynamics of sand fly gut microbial communities in the context of Leishmania infection.ResultsWe observed a decrease in the number of Amplicon Sequence Variants (ASVs) at two key time points: a significant decrease early after infection (Day 2), and a trend toward reduction at late after infection (Day 12). These results were accompanied by noticeable changes in the relative abundance of multiple bacterial families and respective genera with the progression of Leishmania infection in the sand fly midgut, with e.g. Sphingomonas, Ochrobactrum, and Serratia as the most prevalent genera detected, before, early after, and late after infection, respectively. While these results did not overall translate into significant differences in alpha diversity metrics, they did lead to a separation between the 3 groups in the context of a beta diversity analysis, with statistical relevance. Importantly, via an ANCOM-BC analysis we were able to establish Corynebacterium spp. and Enterococcus spp. as potential markers of non-infected and infected sand flies, respectively, as well as Streptococcus spp., Sphingomonas spp., Ralstonia spp., and Abiotrophia spp. as potential specific markers of late infections.ConclusionsOverall, we show that the composition of the gut microbiota of P. duboscqi sand flies changes significantly over the course of an infection with L. major parasites.