Evidence for the classification of a crayfish pathogen as a member of the genus Coxiella

Abstract

Aims: The study aimed to provide characterization of a potential new species of Coxiella, identified following a series of outbreaks of disease in Australian native freshwater crayfish. Methods and Results: PCR primers designed for amplification of Coxiella burnetii genes including 16S rDNA, com1 and sodB were used to amplify homologues in the Coxiella-like crayfish pathogen. Products were then cloned and sequenced. The organism demonstrated a high degree of sequence homology in the highly conserved 16S rDNA (96%) and sodB (99%) genes, as well as the Coxiella sp. specific com1 (100%) gene. Regions flanking the sodB coding sequence demonstrated homology to C. burnetii antioxidant AhpC/Tsa family protein and dihydrodipicolinate reductase gene. Conclusions: The degree of homology between the genes selected and flanking regions suggested the two organisms were sufficiently closely related to belong to the same genus. Significance and Impact of the Study: This study provided evidence for a potential new species in the currently monospecific genus Coxiella, with the only described member being C. burnetii, a category B biological warfare agent. © 2007 The Authors.