RESUMO
1. Interaction between bacteria and host tissue is important, both for primary adhesion and tissue-specific colonisation, as well as for pathogen invasion for different host tissues. 2. Ornithobacterium rhinotracheale is a bacterium associated with respiratory tract infections in poultry. The mechanisms by which O. rhinotracheale causes infection are not known. To date, at least 18 serovars of this bacterium, with or without the ability to agglutinate erythrocytes of chicken and other species, have been identified. 3. The purpose of this work was to evaluate the ability of five references strains, belonging to serovars A, B, C, D and E, to adhere to a culture of primary chicken tracheal cells. 4. Serovars A and B adhered to less than 20% of tracheal cells with no specific adherence pattern. Serovars C, D and E gave adherence values greater than 70%. Serovars C and E showed a diffuse adherence pattern, while serovar D had an aggregated adherence pattern. 5. The adherence ability and pattern could be associated with different pathogenicity mechanisms in the various serovars but more studies are needed to understand the reasons for these differences.