Inhibition of the endosymbiont “Candidatus Midichloria mitochondrii” during 16S rRNA gene profiling reveals potential pathogens in Ixodes ticks from Australia
MetadataShow full item record
Background: The Australian paralysis tick (Ixodes holocyclus) is of significant medical and veterinary importance as a cause of dermatological and neurological disease, yet there is currently limited information about the bacterial communities harboured by these ticks and the risk of infectious disease transmission to humans and domestic animals. Ongoing controversy about the presence of Borrelia burgdorferi sensu lato (the aetiological agent of Lyme disease) in Australia increases the need to accurately identify and characterise bacteria harboured by I. holocyclus ticks. Methods: Universal PCR primers were used to amplify the V1-2 hyper-variable region of bacterial 16S rRNA genes present in DNA samples from I. holocyclus and I. ricinus ticks, collected in Australia and Germany respectively. The 16S amplicons were purified, sequenced on the Ion Torrent platform, and analysed in USEARCH, QIIME, and BLAST to assign genus and species-level taxonomy. Initial analysis of I. holocyclus and I. ricinus identified that > 95 % of the 16S sequences recovered belonged to the tick intracellular endosymbiont “Candidatus Midichloria mitochondrii” (CMM). A CMM-specific blocking primer was designed that decreased CMM sequences by approximately 96 % in both tick species and significantly increased the total detectable bacterial diversity, allowing identification of medically important bacterial pathogens that were previously masked by CMM.Results: Borrelia burgdorferi sensu lato was identified in German I. ricinus, but not in Australian I. holocyclus ticks. However, bacteria of medical significance were detected in I. holocyclus ticks, including a Borrelia relapsing fever group sp., Bartonella henselae, novel “Candidatus Neoehrlichia” spp., Clostridium histolyticum, Rickettsia spp., and Leptospira inadai. Conclusions: Abundant bacterial endosymbionts, such as CMM, limit the effectiveness of next-generation 16S bacterial community profiling in arthropods by masking less abundant bacteria, including pathogens. Specific blocking primers that inhibit endosymbiont 16S amplification during PCR are an effective way of reducing this limitation. Here, this strategy provided the first evidence of a relapsing fever Borrelia sp. and of novel “Candidatus Neoehrlichia” spp. in Australia. Our results raise new questions about tick-borne pathogens in I. holocyclus ticks.
Showing items related by title, author, creator and subject.
Schwarz, Karen Rosemary (2012)A research project was undertaken to study the effect of biosolids on the decay times of enteric pathogens in the soil. This is the most comprehensive study in Australia where the persistence of enteric microorganisms in ...
Acetylcholinesterase 1 in populations of organophosphate-resistant North American strains of the cattle tick, Rhipicephalus microplus (Acari: Ixodidae)Bendele, K.; Guerrero, F.; Miller, R.; Li, A.; Barrero, R.; Moolhuijzen, Paula; Black, M.; McCooke, J.; Meyer, J.; Hill, C.; Bellgard, M. (2015)Rhipicephalus microplus, the cattle fever tick, is a global economic problem to the cattle industry due to direct infestation of cattle and pathogens transmitted during feeding. Cattle fever tick outbreaks continue to ...
Suppressive subtractive hybridization analysis of Rhipicephalus (Boophilus) microplus larval and adult transcript expression during attachment and feedingLew-Tabor, A.; Moolhuijzen, Paula; Vance, M.; Kurscheid, S.; Valle, M.; Jarrett, S.; Minchin, C.; Jackson, L.; Jonsson, N.; Bellgard, M.; Guerrero, F. (2010)Ticks, as blood-feeding ectoparasites, affect their hosts both directly and as vectors of viral, bacterial and protozoal diseases. The tick's mode of feeding means it must maintain intimate contact with the host in the ...