Characterization of the Haemophilus-Like Organism of Infectious Thromboembolic Meningoencephalitis of Cattle

Abstract

SUMMARY The most satisfactory medium for cultivating the bovine Haemophilus -like organism was cystine heart agar enriched with 10% bovine blood and 0.5% yeast extract. Defibrinated bovine blood was superior to lapine blood as a culture medium supplement and much superior to ovine blood. Growth did not occur when serum was substituted for blood. The components of blood essential for bacterial growth were associated chiefly with the red blood cells. Optimal conditions for growth were incubation at 37 C. in a 10% CO 2 atmosphere. Various isolates of the bovine Haemophilus -like organism were anti-genically homologous as determined by agglutination tests. Cross agglutinations were observed with Haemophilus -like and Bordetella bronchiseptica . Cross agglutination did not occur with other hemophilic bacteria. There was no antigenic relationship with Actinobacillus actinoides . The cultural and antigenic characteristics of the organism suggest that it is Haemophilus -like rather than A. actinoidesAik .