The Causative Organism of Contagious Equine Metritis 1977: Proposal for a New Species to be known as Haemophilus equigenitalis

Abstract

The etiological agent of contagious equine metritis (CEM) was investigated bacteriologically in a wide range of cultural and conventional biochemical tests, in the electron microscope, for DNA base composition (36.1% GC), for susceptibility to various antimicrobial agents and antigenically by means of tube and slide agglutination tests. The organism is a fastidious, gram-negative, non acid-fast coccobacillus which in biochemical tests is very unreactive. In conventional tests, only the oxidase, catalase and phosphatase tests were positive. Dependance on neither X nor V factors could be demonstrated, but some stimulation of growth by X factor was observed. The organism could not be identified with any known species and even allocation to an appropriate genus was difficult. Rather than create a new genus of only 1 species defined mainly on negative characters, the organism was proposed as a new species of the genus Haemophilus: H. equigenitalis, type strain NCTC 11184 (61717/77).