AUTHOR=Kumar Deepak , Sharma Surendra Raj , Adegoke Abdulsalam , Kennedy Ashley , Tuten Holly C. , Li Andrew Y. , Karim Shahid 

TITLE=Recently Evolved Francisella-Like Endosymbiont Outcompetes an Ancient and Evolutionarily Associated Coxiella-Like Endosymbiont in the Lone Star Tick (Amblyomma americanum) Linked to the Alpha-Gal Syndrome

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=Volume 12 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.787209

DOI=10.3389/fcimb.2022.787209

ISSN=2235-2988

ABSTRACT=The lone star tick (Amblyomma americanum) is an aggressive human-biting tick that transmits bacterial and viral pathogens, and its bites are suspected of eliciting the Alpha-Gal Syndrome, a newly emerged delayed hypersensitivity following consumption of red meat in the United States. In this study, we utilized a high throughput metagenomic sequencing approach to cataloging the entire microbial communities residing within different developmental stages and tissues of unfed and fed ticks from laboratory-maintained ticks and three new geographical locations in the USA. The quantitative insights into microbial ecology (QIIME2) pipeline were used to perform data analysis and taxonomic classification. Moreover, using a SparCC network construction model, we investigated potential interactions between members of the microbial communities from lab-maintained and field-collected ticks. Overall, Francisellaceae was the most dominant bacteria identified in the microbiome of both lab-raised and field-collected Am. americanum across all tissues and developmental stages. Likewise, microbial diversity was seen to be significantly higher in field-collected ticks compared to lab-maintained ticks as seen with a higher number of both OTUs and measures of species richness. Several potential positive and negative correlations were identified from our network analysis. We observed a strong positive correlation between Francisellaceae, Rickettsiaceae, and Midichloriaceae in both developmental stages and tissues from lab-maintained ticks, while ovarian tissues had a strong positive correlation of bacteria in the family Xanthobacteraceae and Rhizobiaceae. A negative interaction was observed between Coxiellaceae and Francisellaceae in Illinois, and all the bacteria detected from ticks from Delaware were negatively correlated. This study is the first to catalog the microbiome of Am. americanum throughout its developmental stages and different tissue niches and report the potential replacement of Coxiellaceae by Francisellaceae across developmental stages and tissues tested except in ovarian tissues. These unique and significant findings advance our knowledge and open a new avenue of research to further understand the role of tick microbiome in tick-borne diseases and develop a holistic strategy to control Alpha-Gal syndrome.