Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/9/2001
Publication Date: N/A
Technical Abstract: Over the course of the past decade, actinomycetes have been isolated from the placentas of horses diagnosed as suffering from nocardioform placentitis. The incidence of this infection has been generally low, with typically no more than 20 animals affected most years, but the incidence increased through 1999, with placentas from 150 mares found to be infected. Half of the cases result in loss of the foal. A typical actinomycete with branching mycelium was isolated from placental lesions, and a BLAST search of the sequence of the 16S rDNA gene indicated that it was related to members of the suborder Pseudonocardineae. Phylogenetic analysis of a number of isolates revealed a close relationship to Crossiella cryophila, and subsequent polyphasic comparisons determined that these isolates represent a new species of Crossiella, for which the name Crossiella equi is proposed. Other actinomycetes have also been isolated from lesions on equine placentas, and many of these are found to be phylogenetically distributed within the genus Amycolatopsis, where they may also represent new species.