RESUMO
A Coxiella sp. closely related to the agent of Q-fever, Coxiella burnetii, has been associated with mortalities in redclaw crayfish, (Cherax quadricarinatus), in farms and experimental facilities for three decades. Limited sequence data including 16S rRNA have placed the rickettsial species as a new species, candidatus C. cheraxi closely related to C. burnetii. MinION sequencing was conducted on the last remaining sample from an outbreak of disease, TO-98. The accuracy of base pair reads was mostly 99·9% (error rate 1 in 1000) or better. After filtering for reads of co-isolated Citrobacter freundii, 2629 sequences remained with the longest being 12 585 base pairs (bp). The longest 21 sequences are presented with their single best hit statistics when examined by NCBI blastn (nucleotides) and the nucleotides translated into proteins NCBI blastx. All sequences hit with either C. burnetii (29/42, 69%) or Coxiella (10/42, 24%) or rickettsia (3/42, 7%) with an error rate of less than 1 in 1 million for either bp or amino acids. Sequencing in this report confirms candidatus C. cheraxi is a new species very closely related to C. burnetii. SIGNIFICANCE AND IMPACT OF THE STUDY: This work reports on the use of newer technologies on archival samples and provides significantly more data on the currently limited genome data of candidatus Coxiella cheraxi, one of the few species isolated in the genus Coxiella. Candidatus Coxiella cheraxi causes death in redclaw crayfish and has been reported as being closely related to C. burnettii, the agent of Q-fever, based on 16S rRNA sequencing. This work provides confirmation for this claim.
