Bacteriological and serological studies of haemophilus equigenitalis, agent of contagious equine metritis

Seventeen strains of haemophilus equigenitalis isolated from the cervix, clitoris, and urethra of mares were biochemically characterized with the API 10E and APIZYM test kit systems, conventional biochemical tests, and the porphyrin test. Antisera were prepared in rabbits. All of the strains were positive to the porphyrin test, and the requirement for factor X (hemin) or V (nicotinamide adenine dinucleotide) was not shown. Catalase, oxidase, phosphatase, and phosphoamidase tests were positive with all of the strains. Aminopeptidase (arylamidase) activity has been detected on beta-naphthylamide derivatives of eight amino acids and of di- and tripeptides. No glycosidase activity was found. Antisera prepared in rabbits strongly agglutinated all H. equigenitalis strains, but none of the various other bacterial strains. These characteristics should prove to be useful in the identification of H. equigenitalis.