The Nocardia salmonicida clade, including descriptions of Nocardia cummidelens sp nov., Nocardia fluminea sp nov and Nocardia soli sp nov.

Large numbers of strains selectively isolated from soil, water and deterior ating vulcanised natural rubber pipe rings were provisionally assigned to t he genus Nocardia. Twenty-eight representative isolates were found to have chemical and morphological properties typical of nocardiae. These organisms formed a monophyletic clade in the 16S rDNA tree together with Nocardia sa lmonicida. Three of the strains, isolates S1, W30 and R89, were distinguish ed from one another and from representatives of the validly described speci es of Nocardia using genotypic and phenotypic data. These organisms were co nsidered to merit species status and were named Nocardia cummidelens sp. no v., Nocardia fluminea sp. nov. and Nocardia soli sp. nov. respectively. Add itional comparative studies are needed to resolve the finer taxonomic relat ionships of the remaining isolates assigned to the Nocardia salmonicida cla de and to further unravel the extent of nocardial diversity in artificial a nd natural ecosystems.