Principal Research Scholar North Carolina State University Raleigh, North Carolina
Bacterial microbiome of the chigger mite varies by life stage and infection with the scrub typhus pathogen Orientia tsutsugamushi Loganathan Ponnusamy, Alexandra C. Willcox, R. Michael Roe, Silas A. Davidson, Piyada Linsuwanon, Anthony L. Schuster, Allen L. Richards, Steven R. Meshnick, and Charles S. Apperson Scrub typhus is a severe mite-borne infection caused by Orientia tsutsugamushi (Ot), an obligate intracellular bacterium closely related to the genus Rickettsia. The disease occurs in Korea, Japan, southern Asia, the Asian-Pacific region, and northern Australia where an estimated one billion people are at risk. The composition of bacteria populations in deutonymphs, larvae, and adult females and males from laboratory colonies of Leptotrombidium imphalum that were infected and uninfected with O. tsutsugamushi were explored by high-throughput sequencing of the bacterial 16S rRNA gene. Surprisingly, the bacterial microbiomes of infected adult females were dominated by sequences of O. tsutsugamushi and an unidentified species of Amoebophilaceae, comprising 98.2% of bacterial sequences. α-diversity analyses revealed significant variations in species diversity between infected and uninfected adult mites. Beta diversity analyses also showed that most of the variation in bacterial diversity across the samples could be attributed to infection with Orientia tsutsugamushi and the Amoebophilaceae bacterium. Our results provide the basis for further studies to determine the influence of the novel Amoebophilaceae species on the bacterial microbiome and on vector susceptibility to and transovarial transmission of O. tsutsugamushi.
