title: Bacterial Profiling Reveals Novel "Ca. Neoehrlichia", Ehrlichia, and Anaplasma Species in Australian Human-Biting Ticks.
abstract: In Australia, a conclusive aetiology of Lyme disease-like illness in human patients remains elusive, despite growing numbers of people presenting with symptoms attributed to tick bites. In the present study, we surveyed the microbial communities harboured by human-biting ticks from across Australia to identify bacteria that may contribute to this syndrome. Universal PCR primers were used to amplify the V1-2 hyper-variable region of bacterial 16S rRNA genes in DNA samples from individual Ixodes holocyclus (n = 279), Amblyomma triguttatum (n = 167), Haemaphysalis bancrofti (n = 7), and H. longicornis (n = 7) ticks. The 16S amplicons were sequenced on the Illumina MiSeq platform and analysed in USEARCH, QIIME, and BLAST to assign genus and species-level taxonomies. Nested PCR and Sanger sequencing were used to confirm the NGS data and further analyse novel findings. All 460 ticks were negative for Borrelia spp. by both NGS and nested PCR analysis. Two novel "Candidatus Neoehrlichia" spp. were identified in 12.9% of I. holocyclus ticks. A novel Anaplasma sp. was identified in 1.8% of A. triguttatum ticks, and a novel Ehrlichia sp. was identified in both A. triguttatum (1.2%) ticks and a single I. holocyclus (0.6%) tick. Further phylogenetic analysis of novel "Ca. Neoehrlichia", Anaplasma and Ehrlichia based on 1,265 bp 16S rRNA gene sequences suggests that these are new species. Determining whether these newly discovered organisms cause disease in humans and animals, like closely related bacteria do abroad, is of public health importance and requires further investigation.
authors.affiliation: Vector and Water-borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Gofton
authors.affiliation: Department of Medical Entomology, Pathology West and Institute for Clinical Pathology and Medical Research, Westmead Hospital, Westmead, New South Wales, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Doggett
authors.affiliation: Emergency Department, Mona Vale Hospital, New South Wales, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Ratchford
authors.affiliation: Vector and Water-borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors.forename: Charlotte L
authors.initials: CL
authors.lastname: Oskam
authors.affiliation: Vector and Water-borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors.forename: Andrea
authors.initials: A
authors.lastname: Paparini
authors.affiliation: Vector and Water-borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors.forename: Una
authors.initials: U
authors.lastname: Ryan
authors.affiliation: Vector and Water-borne Pathogen Research Group, School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Irwin
mesh_terms: D000709:Anaplasma / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification* / Q000502:physiology; D000818:Animals; D001315:Australia; D001499:Bayes Theorem; D004536:Ehrlichia / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification* / Q000502:physiology; D014644:Genetic Variation; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D018884:Ixodes / Q000382:microbiology* / Q000502:physiology; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013559:Symbiosis
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S