AUTHOR=Adegoke Abdulsalam , Kumar Deepak , Budachetri Khemraj , Karim Shahid 

TITLE=Hematophagy and tick-borne Rickettsial pathogen shape the microbial community structure and predicted functions within the tick vector, Amblyomma maculatum

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.1037387

DOI=10.3389/fcimb.2022.1037387

ISSN=2235-2988

ABSTRACT=<sec><title>Background</title><p>Ticks are the primary vectors of emerging and resurging pathogens of public health significance worldwide. Analyzing tick bacterial composition, diversity, and functionality across developmental stages and tissues is crucial for designing new strategies to control ticks and prevent tick-borne diseases.</p></sec><sec><title>Materials and methods</title><p>Here, we explored the microbial communities across the developmental timeline and in different tissues of the Gulf-Coast ticks (<italic>Amblyomma maculatum</italic>). Using a high-throughput sequencing approach, the influence of blood meal and <italic>Rickettsia parkeri</italic>, a spotted fever group rickettsiae infection in driving changes in microbiome composition, diversity, and functionality was determined.</p></sec><sec><title>Results</title><p>This study shows that the core microbiome of <italic>Am. maculatum</italic> comprises ten core bacterial genera. The genus <italic>Rickettsia, Francisella</italic>, and <italic>Candidatus_Midichloria</italic> are the key players, with positive interactions within each developmental stage and adult tick organ tested. Blood meal and <italic>Rickettsia parkeri</italic> led to an increase in the bacterial abundance in the tissues. According to functional analysis, the increase in bacterial numbers is positively correlated to highly abundant energy metabolism orthologs with blood meal. Correlation analysis identified an increase in OTUs identified as <italic>Candidatus Midichloria</italic> and a subsequent decrease in <italic>Francisella</italic> OTUs in <italic>Rickettsia parkeri</italic> infected tick stages and tissues. Results demonstrate the abundance of <italic>Rickettsia</italic> and <italic>Francisella</italic> predominate in the core microbiome of <italic>Am. maculatum</italic>, whereas <italic>Candidatus_Midichloria</italic> and <italic>Cutibacterium</italic> prevalence increase with <italic>R. parkeri-infection</italic>. Network analysis and functional annotation suggest that <italic>R. parkeri</italic> interacts positively with <italic>Candidatus_Midichloria</italic> and negatively with <italic>Francisella</italic>.</p></sec><sec><title>Conclusion</title><p>We conclude that tick-transmitted pathogens, such as <italic>R. parkeri</italic> establishes infection by interacting with the core microbiome of the tick vector.</p></sec>