High-throughput sequencing to detect the bacterial microbiome in Ixodes granulatus in China

Abstract

Abstract Background Ixodes granulatus is of significant research value as the primary vector of Lyme disease in Asia, yet the bacterial community structure and diversity carried by these ticks have not been reported so far. Part of bacteria in ticks can affect tick development and the transmission of tick-borne pathogens. With the emergence of new pathogens, it is necessary to identify the bacterial microbiome carried by I. granulatus. Methods Ixodes granulatus were collected from rodent animals in the Binchuan, China. The bacterial DNA was extracted from non-engorged adult female I. granulatus. Sequencing of the V3-V4 regions of the 16S rRNA genes was performed using the Illumina NovaSeq sequencing platform. Initial data was assembled in FLASH, QIIME, and UCHIME algorithm. Uparse and MUSCLE software were used to annotate and analyze the effective data. Result The predominant phyla in all samples were Firmicutes, Proteobacteria, Actinobacteria, and Spirochaetota. The major genera were Spiroplasma, Staphylococcus, Candidatus-Lariskella, Corynebacterium, Ralstonia, Borreliella (Borrelia), Vibrio, Bacillus, and Listeria. Staphylococcus xylosus, Ralstonia pickettii, Corynebacterium mastitidis, Bryopsis hypnoides, and Vibrio metschnikovii were dominant bacterial species. The results demonstrated that there were discrepancies in bacterial microbiome richness and diversity among different individual ticks of the same species, and found a large number of pathogenic bacteria and opportunistic pathogens, yet Coxiella and Rickettsia were not detected. Conclusion The results presented here speculate that Spiroplasma is the endosymbiont of I. granulatus and competitively inhibits Borrelia. Our study suggested that Binchuan is at risk of Lyme disease transmission and needs to be taken seriously. These findings may serve fundamental knowledge for developing novel strategies to control ticks and their transmission of diseases.