title: The bacterial microbiome of Dermacentor andersoni ticks influences pathogen susceptibility.
abstract: Ticks are of medical importance owing to their ability to transmit pathogens to humans and animals. The Rocky Mountain wood tick, Dermacentor andersoni, is a vector of a number of pathogens, including Anaplasma marginale, which is the most widespread tick-borne pathogen of livestock. Although ticks host pathogenic bacteria, they also harbor bacterial endosymbionts that have a role in tick physiology, survival, as well as pathogen acquisition and transmission. The goal of this study was to characterize the bacterial microbiome and examine the impact of microbiome disruption on pathogen susceptibility. The bacterial microbiome of two populations of D. andersoni with historically different susceptibilities to A. marginale was characterized. In this study, the microbiome was disrupted and then ticks were exposed to A. marginale or Francisella novicida to determine whether the microbiome correlated with pathogen susceptibility. Our study showed that an increase in proportion and quantity of Rickettsia bellii in the microbiome was negatively correlated to A. marginale levels in ticks. Furthermore, a decrease in Francisella endosymbionts was associated with lower F. novicida infection levels, demonstrating a positive pathogen-endosymbiont relationship. We demonstrate that endosymbionts and pathogens have varying interactions, and suggest that microbiome manipulation may provide a possible method for biocontrol by decreasing pathogen susceptibility of ticks.
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA.
authors.forename: Cory A
authors.initials: CA
authors.lastname: Gall
authors.affiliation: Animal Disease Research Unit, US Department of Agriculture, Agricultural Research Service, Pullman, WA, USA.
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Reif
authors.affiliation: Animal Disease Research Unit, US Department of Agriculture, Agricultural Research Service, Pullman, WA, USA.
authors.forename: Glen A
authors.initials: GA
authors.lastname: Scoles
authors.affiliation: Animal Disease Research Unit, US Department of Agriculture, Agricultural Research Service, Pullman, WA, USA.
authors.forename: Kathleen L
authors.initials: KL
authors.lastname: Mason
authors.affiliation: Animal Disease Research Unit, US Department of Agriculture, Agricultural Research Service, Pullman, WA, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Mousel
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA.|Animal Disease Research Unit, US Department of Agriculture, Agricultural Research Service, Pullman, WA, USA.|Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, USA.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Noh
authors.affiliation: Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA.|Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA, USA.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Brayton
mesh_terms: D042322:Anaplasma marginale / Q000472:pathogenicity*; D000818:Animals; D003870:Dermacentor / Q000382:microbiology* / Q000502:physiology; D005603:Francisella / Q000472:pathogenicity*; D006801:Humans; D064307:Microbiota; D012281:Rickettsia / Q000254:growth & development*; D013559:Symbiosis