Adherence of Ornithobacterium rhinotracheale to chicken embryo lung cells as a pathogenic mechanism

Abstract

Ornithobacterium rhinotracheale is a bacterium that causes respiratory disease in birds and it has been isolated in countries with a large poultry production, including Mexico. The pathogenicity mechanisms of this bacterium have not been completely elucidated yet. The capacity of the bacterium to adhere to epithelial cells of chicken in vitro has been evidenced, and since this bacterium has been isolated from the lungs and air sacs of several avian species, the aim of this study was to determine if this bacterium can adhere to chicken lung cells. We used five O. rhinotracheale reference serovars (A-E) that were in contact with primary lung cells cultured from a 19-day-old chicken embryo. O. rhinotracheale adherence was evaluated through optical and transmission electron microscopies. The results revealed that O. rhinotracheale is capable of adhering to chicken embryo lung cells within 3 h of incubation with a diffuse adherence pattern. The adherence percentages of the chicken embryo lung cells were 51-96% according to the serovar of the bacterium. Relative adherence was from 4 to 8 bacteria per cell. Transmission electron microscope data revealed intracellular bacteria inside a vacuole in less than 3 h of incubation.

Ornithobacterium rhinotracheale: An Update Review about An Emerging Poultry Pathogen

“…Currently, 18 ORT serotypes (A-R) have been reported, with no direct relationship with virulence. Due to the difficulty of the serotyping process, it has been suggested that there are new serotypes yet to be determined [2,3,21].…”

“…Cell viability studies have shown that ORT can adhere to chicken embryo lung cells after 3 h incubation, resulting in a diffuse growth pattern. There are appendages and hemagglutinins, which probably contributed to the adhesion, suggesting the presence of host cell receptors that recognize ORT adhesins [21].…”

Research Note: Serological investigation of Ornithobacterium rhinotracheale infection in China

“…ORT infection is common in turkeys and chickens and can be transmitted horizontally and vertically. To date, 18 ORT serotypes (A–R) have been identified, but no direct relationship with virulence has been reported ( Zahra et al., 2013 ; De la Rosa-Ramos et al., 2018 ; Montes et al., 2018 ). Analysis of the rpoB gene has been used to distinguish similar strains ( Veiga et al., 2019 ).…”

Comparison of the first Iranian native Ornithobacterium rhinotracheale vaccine with conventional vaccine: A challenge study

“…The bacterium primarily infects the trachea, lungs, and air sacs, but can also manifest as a systemic disease [8,12]. The ORT bacterium is most commonly isolated from the trachea and lungs of naturally or experimentally infected birds [17][18][19]. In our study, the bacterium was not isolated from the respiratory system by the culture in the vaccinated groups in the DAC.…”