IDENTIFICATION AND SEROTYPING OF ORNITHOBACTERIUM-RHINOTRACHEALE

In the present study 443 strains of Ornithobacterium rhinotracheale, a causative agent of respiratory disease in fowl, were investigated bio chemically and serologically, In both ways O. rhinotracheale could be differentiated from other gram-negative rods and, more particularly, f rom the Pasteurella-like bacteria potentially pathogenic for fowl, For the biochemical characterization of O. rhinotracheale the API 2ONE id entification strip proved to be useful, although O. rhinotracheale is not included in the API system, Serologically, by using monovalent ant isera in agar gel precipitation (AGP) tests and enzyme-linked immunoso rbent assays (ELISAs), seven serotypes (serotypes A to G) of O. rhinot racheale could be discriminated, The AGP test was chosen as the prefer red method to be used for serotyping, Isolates of serotype A were foun d to be the most prevalent, especially in chickens, Isolates from turk eys were more heterogeneously divided over the serotypes, Some strains showed cross-reactivity between serotypes A, B, and E, Five O. rhinot racheale strains could not be serotyped with the available antisera, R elationships between the geographic origin and the serotypes were foun d, By the ELISA the presence of antibodies against O. rhinotracheale c ould be detected in 1-day-old birds as well as in birds with clinical signs, and therefore, it might be useful for diagnostic purposes.