actinobacillus rossii actinobacillus rossii actinobacillus rossii is a bacterium. it was first isolated from the vaginas of postparturient sows. actinobacillus rossii scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: pasteurellales family: pasteurellaceae genus: actinobacillus species: a. rossii binomial name actinobacillus rossiisneath and stevens 1990