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ARS Home » Pacific West Area » Pullman, Washington » Animal Disease Research » Research » Publications at this Location » Publication #328774

Research Project: Development of Strategies to Control Anaplasmosis

Location: Animal Disease Research

Title: The characterization and manipulation of the bacterial microbiome of the Rocky Mountain wood tick, Dermacentor andersoni

Author
item Clayton, Katie - Washington State University
item Gall, Cory - Washington State University
item Mason, Kathleen
item Brayton, Kelly - Washington State University
item Scoles, Glen

Submitted to: Parasites & Vectors
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/3/2015
Publication Date: 12/10/2015
Citation: Clayton, K.A., Gall, C.A., Mason, K.L., Brayton, K.A., Scoles, G.A. 2015. The characterization and manipulation of the bacterial microbiome of the Rocky Mountain wood tick, Dermacentor andersoni. Parasites & Vectors. 8:632.

Interpretive Summary: Ticks are the most economically impactful vectors of human and animal pathogens in North America, The Rocky Mountain wood tick, Dermacentor andersoni (Acari: Ixodidae), transmits Rickettsia rickettsii and Anaplasma marginale to humans and cattle, respectively. In recent years, studies have shown that populations of symbiotic organisms living within the tick, known as the microbiome, are involved in a number of biochemical and physiological functions. Developing an understanding of the bacterial microbiome of D. andersoni will be a pivotal step towards understanding how these symbiont populations interact with their tick hosts. In this study, we have used high-throughput sequence analysis to show that the composition of endosymbionts in the midgut and salivary glands in adult ticks is dynamic over three generations. Four Proteobacteria genera, Rickettsia, Francisella, Arsenophonus, and Acinetobacter, were identified as predominant symbionts in the gut and salivary glands of ticks. Ticks feeding on to cattle treated with therapeutic doses of the broad-spectrum antibiotic, oxytetracycline, had significantly reduced reproductive fitness and the proportions of predominant genera of microbes were affected. Additionally, Acinetobacter, a free-living ubiquitous microbe, invaded the bacterial microbiome at different proportions based on antibiotic treatment status suggesting that microbiome composition may have a role in susceptibility to environmental contaminants. This study confirmed that manipulation of the microbiome can affect tick fitness and may be a potential method for biocontrol.

Technical Abstract: Background: In North America, ticks are the most economically impactful vectors of human and animal pathogens. The Rocky Mountain wood tick, Dermacentor andersoni (Acari: Ixodidae), transmits Rickettsia rickettsii and Anaplasma marginale to humans and cattle, respectively. In recent years, studies have shown that symbiotic organisms are involved in a number of biochemical and physiological functions. Characterizing the bacterial microbiome of D. andersoni is a pivotal step towards understanding symbiont-host interactions. Findings: In this study, we have shown by high-throughput sequence analysis that the composition of endosymbionts in the midgut and salivary glands in adult ticks is dynamic over three generations. Four Proteobacteria genera, Rickettsia, Francisella, Arsenophonus, and Acinetobacter, were identified as predominant symbionts in these two tissues. Exposure to therapeutic doses of the broad-spectrum antibiotic, oxytetracycline, affected both proportions of predominant genera and significantly reduced reproductive fitness. Additionally, Acinetobacter, a free-living ubiquitous microbe, invaded the bacterial microbiome at different proportions based on antibiotic treatment status suggesting that microbiome composition may have a role in susceptibility to environmental contaminants. Conclusions: This study characterized the bacterial microbiome in D. andersoni and determined the generational variability within this tick. Furthermore, this study confirmed that microbiome manipulation is associated with tick fitness and may be a potential method for biocontrol.