Tick saliva microbiomes isolated from engorged and partially fed adults of Haemaphysalis flava tick females

Abstract

The tick Haemaphysalis flava is one of the most significant blood-feeding arthropod parasites and is a vector for numerous human and animal pathogens. However, a comprehensive investigation of the microbial communities found in the saliva of this tick species is lacking. This study used 16S rRNA Illumina sequencing to characterize the compositions of microbiomes present in saliva and whole tick samples isolated from engorged and partially fed adult H. flava females. This revealed that the bacterial diversity present in tick saliva increased after a prolonged blood meal, and that the species diversity found in saliva was significantly higher than that of whole ticks. Three bacteria phyla, in particular, made up more than 80% of the microbial community across all samples-Proteobacteria, Firmicutes and Actinobacteria. Furthermore, some of the genera identified in this study had not previously been reported in ticks before, such as Facklamia, Vagococcus, Ruminococcus, Lachnospira, Bradyrhizobium, Peptostreptococcus, Jeotgalicoccus, Roseburia, Brachybacterium, Sporosarcina, u114, Megamonas and Dechloromonas. Finally, we found that many of the isolated bacteria were opportunistic pathogens, indicating a potential risk to humans and livestock exposed to H. flava.These results will contribute to fully understanding the transmission of tick-borne pathogens. K E Y W O R D Sbacteria, Haemaphysalis flava, microbiome, saliva | INTRODUCTIONHaemaphysalis flava (Acari: Ixodidae) is a prevalent hard tick species found in many countries that feeds on a wide variety of hosts, including hares, dogs, cows, horses, wild boar, deer, bears, pigs, cattle, sheep, goats, hedgehogs, pandas, cats, squirrels and golden pheasants (He, Tang, & Cheng, 2016). As a vector for numerous pathogens, including encephalitis virus (Ko et al., 2010), Borrelia burgdorferi (Moon et al., 2013), Rickettsia (Someya, Ito, Maeda, & Ikenaga, 2015), Francisella tularensis (Kim et al., 2005), Bartonella (Ozawa et al., 1982), Anaplasma and Ehrlichia (Rar et al., 2010), H. flava has emerged as a significant threat to public health.Tick saliva plays a pivotal role in pathogen transmission (Nuttall & Labuda, 2004) and studying the microbes that inhabit it can contribute to both conventional disease discovery (in which a pathogen is discovered in a host and then identified in the tick population) and reverse discovery (in which a potential pathogen is characterized in ticks and then is subsequently shown to cause disease) (Tijsse-Klasen, Koopmans, & Sprong, 2014). However, information on the microbial populations present in tick saliva remains scarce. To date, the saliva microbiomes of Amblyomma maculatum (Budachetri et al., 2014) and Rhipicephalus microplus (Xiang, Poźniak, & Cheng, 2017) are the only two that have been surveyed. The microflora of saliva isolated from H. flava has been partially analysed using PCR-denaturing gradient gel electrophoresis (PCR-DGGE), but this system is unable to reveal in detail the microbial communities of saliva (He et al...

Metagenomic profile of the bacterial communities associated with Ixodes granulatus (Acari: Ixodidae): a potential vector of tick-borne diseases

“…Previous studies on other Ixodes species, such as Ixodes ricinus (Kowalec et al 2019) and Ixodes scapularis (Narasimhan et al 2014), have recorded a higher prevalence of Rickettsiales, considered as endosymbionts, and in the case of the genus Rickettsia , as disease-causing in vertebrates. The presence of Bradyrhizobium (Order: Rhizobiales) in all 9 samples in this study is not novel to the Ixodidae ticks, as it has been previously documented in ticks, but the function of the bacteria remains scarce in literature (He et al 2018, Thapa et al 2019). The Gram-negative soil bacteria contain nitrogen-fixing species that live in a symbiotic relationship with plant roots and can be in contact with ticks during their natural cycle or commensalism in the environment (Greay et al 2018).…”

Identification of microbial taxa present in Ctenocephalides felis (cat flea) reveals widespread co-infection and associations with vector phylogeny

“…Thirteen of 457 (3%) genera exceeded this threshold (Additional file 1 : Fig. S1): Achromobacter [ 68 , 69 ] , Anaerococcus [ 70 – 73 ] , Bacteroides [ 74 , 75 ] , Blastomonas [ 76 , 77 ], Clostridium sensu stricto 5 [ 78 ], Lachnoclostridium [ 79 ] , Methanothermobacter [ 80 ] , Peptoniphilus [ 81 , 82 ] , Peptostreptococcus [ 82 , 83 ], and Rhodococcus [ 84 , 85 ]. A literature search evaluating previous reports of these genera and the rigor of the contaminant filtering in these publications supported the idea that three of these genera ( Achromobacter , Peptoniphilus , and Rhodococcus ) should be considered candidate C. felis microbiome members.…”

“…Thirteen of 457 (3%) genera exceeded this threshold (Additional file 1: Fig. S1): Achromobacter [68,69], Anaerococcus [70][71][72][73], Bacteroides [74,75], Blastomonas [76,77], Clostridium sensu stricto 5 [78], Lachnoclostridium [79], Methanothermobacter [80], Peptoniphilus [81,82], Peptostreptococcus [82,83], and Rhodococcus [84,85].…”

A glimpse of the bacteriome of Hyalomma dromedarii ticks infesting camels reveals human Helicobacter pylori pathogen

“…Prior to 16S rRNA library preparation, extracted DNA samples were pooled because of the high financial burden of performing sequencing for each individual tick. The DNA of 62 individual ticks were divided into two individual samples (consisting of sample 99 and 100) and eight pooled samples (named 28,29,30,55,64,65, 71 and 73.01). Each pool composed of 7 tick DNA samples (total 42 DNA samples) except pool 71 and 73.01 each composed of 9 tick DNA samples (total 18 DNA samples).…”

“…Relative abundance of tick bacteria phyla classified in pooled ticks:28,29,30,55, 64, 65, 71, 73.01 and individual ticks 96, 100. Values were presented as %.…”