Phlebotomus duboscqi gut microbiota dynamics in the context of Leishmania infection

The 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 their gut microbial communities is essential. 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. Here, we address this limitation.

P. duboscqi midguts were dissected both before and at different days after L. major infection and subjected to genomic DNA extraction followed by amplification of the V3-V4 hypervariable regions of the 16S rRNA, sequencing, and metagenomics analysis.

We observed a decrease in the number of Amplicon Sequence Variants (ASVs) early after infection, at D2, and late after infection, at D12. More so Sphingomonas, Ochrobactrum, and Serratia emerged as the most prevalent genera in relative terms, before, early after, and late after infection, respectively. These results translated into a separation between the 3 groups in the context of a beta diversity analysis, with statistical relevance. Importantly, 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 (ANCOM-BC analysis).

Overall, 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.