Co-presence of the Borrelia burgdorferi sensu lato complex species shift the sequence read abundances of tick microbiomes in two German locations

The distribution of human Lyme borreliosis (LB) is assumed to be almost equal in Germany, indicating that the members of the pathogenic Borrelia burgdorferi sensu lato (Bb) complex are similarly distributed as part of the tick microbiome. The aim of this study was to differentiate if the co-presence of Bb occurs with a defined tick microbiome composition or not. Furthermore, the effect of location on tick microbiome composition was addressed for Esslingen (Baden-Wuerttemberg) and Weiden (Bavaria). Therefore, nucleic acid extracts from 82 Borrelia-positive and 118 Borrelia-negative ticks sampled from both districts were selected. Nucleic acid extracts were used for Bb diagnostics based on qPCR and multilocus sequence typing (MLST) and bacterial 16S rRNA gene amplicon sequencing followed by network analyses. As a result, the co-presence of Bb shifted the sequence read abundances of Ca. Midichloria, Rickettsia, Pseudomonas, Staphylococcus, and Ca. Neoehrlichia and their topological roles in the tick microbiome. Moreover, the location was less important in the tick microbiome composition but shifted significantly sequence read abundances of Pseudomonas and Wolbachia. Nevertheless, the topological role of microbial members revealed that location characteristics were of great importance. Since the presence of Bb with other tick-associated pathogens varies regionally, we suggest that a bacterial 16S rRNA gene-based microbiome survey is part of the routine diagnostics for both tick and host if Bb was detected. This diagnostic extension will help to optimize therapeutic approaches against Bb infection and co-occurring pathogens.