Novel Francisella-like endosymbiont and Anaplasma species from Amblyomma nodosum hosted by the anteater Tamandua Mexicana in Mexico

Abstract

The microbiome represents a complex network among the various members of the community of microorganisms that are associated with a host. The composition of the bacterial community is essential to supplement multiple metabolic pathways that the host lacks, particularly in organisms with blood-sucking habits such as ticks. On the other hand, some endosymbionts showed some competence with potentially pathogenic microorganisms. Francisella-like endosymbionts (FLEs) encompass a group of gamma-proteobacterias that are closely related to Francisella tularensis, but are usually apathogenic, which brings nutrients like vitamin B and other cofactors to the tick. It has been postulated that the main route of transmission of FLE is vertical; however, evidence has accumulated regarding the possible mechanism of horizontal transmission. Despite growing interest in knowledge of endosymbionts in the Neotropical region, the efforts related to the establishment of their inventory for tick communities are concentrated in South and Central America, with an important gap in knowledge in Mesoamerican countries such as Mexico. For this reason, the aim of this work was to evaluate the presence and diversity of endosymbionts in the highly host-specialized tick Amblyomma nodosum collected from the anteater Tamandua mexicana in Mexico. We analysed 36 A. nodosum for the presence of DNA of endosymbiont (Coxiella and Francisella) and pathogenic (Anaplasma, Borrelia, Ehrlichia and Rickettsia) bacteria. The presence of a member of the genus Francisella and Candidatus Anaplasma brasiliensis was demonstrated. Our findings provide information on the composition of A. nodosum's microbiome, increasing the inventory of bacterial species associated with this hard tick on the American continent.

Keywords: Candidatus anaplasma brasiliensis; Francisella endosymbiont; Hard tick; Mexico; Microbiome; Mymercophagidae.