Another tick bites the dust: exploring the association of microbial composition with a broad transmission competence of tick vector species.

Abstract

Ticks harbor and transmit many different pathogens. While some species are competent vectors of a single pathogen, mono-competent vectors (MCV), other species are proven to be competent vectors of several pathogens, pluri-competent vectors (PCV). Such a difference in vector competence might be related to the microbiome. To better comprehend its influence on the vector competence of ticks for one or several pathogens, a data-driven approach using publicly available databases was applied on bacterial 16S rRNA from MCV and PCV tick species. Alpha and beta diversity, co-occurrence networks, and functional profiles were analyzed. A differential analysis was performed to identify bacterial genera associated with PCV ticks. These tick species presented higher richness, and the bacterial composition showed a significant difference between MCV and PCV ticks. The bacteria genera of PCV ticks demonstrated fewer correlations within each other in comparison with MCV ticks. The differential analysis revealed 14 bacteria genera related to PCV tick species, such as Rickettsia, Staphylococcus, and Corynebacterium. Using 24 differently abundant genera, tick samples from another data set could be classified into either PCV or MCV with high accuracy and concordance. Moreover, pathway regulation related to reactive oxygen species detoxification, β-Lactam resistance, and dTDP-L-rhamnose biosynthesis could be participating in the competence of PCV ticks for several tick-borne pathogens. These findings enlighten our understanding of the bacteria community's role on some tick species' broad vector competence.IMPORTANCESome tick species are competent to transmit more than one pathogen while other species are, until now, known to be competent to transmit only one single or any pathogen. Such a difference in vector competence for one or more pathogens might be related to the microbiome, and understanding what differentiates these two groups of ticks could help us control several diseases aiming at the bacteria groups that contribute to such a broad vector competence. Using 16S rRNA from tick species that could be classified into these groups, genera such as Rickettsia and Staphylococcus seemed to be associated with such a broad vector competence. Our results highlight differences in tick species when they are divided based on the number of pathogens they are competent to transmit. These findings are the first step into understanding the relationship between one single tick species and the pathogens it transmits.