Two genetic clusters in swine hemoplasmas revealed by analyses of the 16s rRNA and RNase P RNA genes

Abstract

Only two hemoplasma species, Eperythrozoon parvum and Mycoplasma suis, have been recognized in pigs. Here we demonstratethe genetic variations among six hemoplasma strains detected from pigs, by analyzing the 16S rRNA and RNase P RNA (rnpB)genes, and propose a novel hemoplasma taxon that has not been described previously. Phylogenetic trees based on the nucleotidesequence of the 16S rRNA gene indicated that these six hemoplasmas were divided into two clusters representing M. suis and a noveltaxon. We further examined the primary and secondary structures of the nucleotide sequences of the rnpB gene of the novel taxon, andfound it distinct from that of M. suis. In conclusion, we unveiled a genetic cluster distinct from M. suis, suggesting a new swine hemoplasmaspecies or E. parvum. Our findings also suggest that this novel cluster should be included in the genus Mycoplasma.