Reptile-associated Borrelia species in the goanna tick (Bothriocroton undatum) from Sydney, Australia

Abstract

BackgroundKnowledge on the capacity of Australian ticks to carry Borrelia species is currently limited or missing. To evaluate the potential of ticks to carry bacterial pathogens and their DNA, it is imperative to have a robust workflow that maximises recovery of bacterial DNA within ticks in order to enable accurate identification. By exploiting the bilateral anatomical symmetry of ticks, we were able to directly compare two DNA extraction methods for 16S rRNA gene diversity profiling and pathogen detection. We aimed to assess which combination of DNA extraction and 16S rRNA hypervariable region enables identification of the greatest bacterial diversity, whilst minimising bias, and providing the greatest capacity for the identification of Borrelia spp.ResultsWe collected Australian endemic ticks (Bothriocroton undatum), isolated DNA from equal tick halves using two commercial DNA extraction methods and sequenced samples using V1-V3 and V3-V4 16S rRNA gene diversity profiling assays. Two distinct Borrelia spp. operational taxonomic units (OTUs) were detected using the V1-V3 16S rRNA hypervariable region and matching Borrelia spp. sequences were obtained using a conventional nested-PCR. The tick 16S rRNA gene diversity profile was dominated by Rickettsia spp. (98–99%), while the remaining OTUs belonged to Proteobacteria (51–81%), Actinobacteria (6–30%) and Firmicutes (2–7%). Multiple comparisons tests demonstrated biases in each of the DNA extraction kits towards different bacterial taxa.ConclusionsTwo distinct Borrelia species belonging to the reptile-associated Borrelia group were identified. Our results show that the method of DNA extraction can promote bias in the final microbiota identified. We determined an optimal DNA extraction method and 16S rRNA gene diversity profile assay that maximises detection of Borrelia species.Electronic supplementary materialThe online version of this article (doi: 10.1186/s13071-017-2579-5) contains supplementary material, which is available to authorized users.

Bacterial community profiling highlights complex diversity and novel organisms in wildlife ticks

“…In the present study, bacterial profiling of I. tasmani included ticks from three states (NSW, QLD, TAS) and seven host species. With this in mind, we suggest that future studies should combine careful taxonomic status identity with data on microbial communities of I. study are in line with previous research overseas (Zhang et al, 2014;Kurilshikov et al, 2015;Sperling et al, 2017) and in Australia (Gofton et al, 2015b;Panetta et al, 2017). Molecular tools continue to develop at a rapid rate with an increasing shift towards whole-genome or shotgun sequencing (sequencing the full range of nucleic acids present in a metagenomic sample).…”

Detection and isolation of tick‐borne bacteria (Anaplasma spp., Rickettsia spp., and Borrelia spp.) in Amblyomma varanense ticks on lizard (Varanus salvator)

“…The similarity of sequence of 16S rDNA from isolates was 98% to 99% when compared with Borrelia spp. isolated from Bothriocroton undatum (MG004679 or MG004684 in Figure ) ticks that were collected from wild lace lizard ( Varanus varius ) in Australia . Phylogenetic analysis based on 16S rDNA and flaB demonstrated that isolates in this study formed a monophyletic group and belonged to REP borreliae (Figures and S2).…”

“…Bothriocroton undatum (MG004679 or MG004684 in Figure 2) ticks that were collected from wild lace lizard (Varanus varius) in Australia. 6 Phylogenetic analysis based on 16S rDNA and flaB demonstrated that isolates in this study formed a monophyletic group and belonged to REP borreliae (Figures 2 and S2). This is the first study to isolate and perform molecular characterization of a novel species of REP borreliae from Am.…”

“…flavomaculatum , which feeds on savannah monitor ( Varanus exanthematicus ) in Poland, were positive for Anaplasma phagocytophilum , the causative agent of human granulocytic anaplasmosis . Several reptile‐associated (REP) borreliae have been reported in ticks of the genera Hyalomma , Bothriocroton , Amblyomma , and/or Aponomma found in Asia, Australia, Africa, and the Middle East . In addition, the causative agent of African tick‐bite fever, Rickettsia africae , and that of tick‐borne lymphadenopathy, Rickettsia raoultii , have been detected in reptile‐associated ticks .…”

“…2,3 Several reptile-associated (REP) borreliae have been reported in ticks of the genera Hyalomma, Bothriocroton, Amblyomma, and/or Aponomma found in Asia, Australia, Africa, and the Middle East. [4][5][6] In addition, the causative agent of African tick-bite fever, Rickettsia africae, and that of tick-borne lymphadenopathy, Rickettsia raoultii, have been detected in reptile-associated ticks. 7 Some reptileassociated ticks infested humans and/or livestock 8 as well as reptiles, including the water monitor (Varanus salvator), which inhabit cities and may be in close relation with human habitat.…”