The usefulness of the API 20 E classification system in the identification of Actinobacillus actinomycetem comitans, Actinobacillus seminis and Pasteurella haemolytica

Abstract

The prepuces of lambs aged 6-8 months and semen of 2 adult rams were found to be infected with gram-negative, non-motile, non-haemolytic, pleomorphic bacilli. These organisms were compared with those of known strains of Actinobacillus actinomycetem comitans, Actinobacillus seminis and Pasteurella haemolytica, using the API 20 E classification system. Applying the principles of numerical taxonomy, the majority of suspected strains of A. seminis could be classified as A. actinomycetem comitans and 3 examples as Histophilus ovis. Although some of the suspected strains of A. seminis could be classified as P. haemolytica, obvious differences between the genera Actinobacillus and Pasteurella were evident.