The pathogenesis of Haemophilus parasuis, that bacterium causing Glässer's disease, depends on its ability to interact with endothelial cells and invade adjacent tissues, according to Rafael Frandoloso of the University of León in Spain.

In a study with colleagues there and at the University of Passo Fundo in Brazil and published in BMC Veterinary Research, he investigated the abilities of eight H. parasuis reference strains belonging to serovars 1, 2, 4, 5, 7, 9, 10 and 13 to adhere to and invade porcine aortic endothelial cells (AOC-45 cell line).

The strains belonging to serovars 1, 2 and 5 were able to attach at high rates between 60 and 240 minutes of incubation, and serovars 4, 7 and 13 had moderate attachment rates; however, the strains belonging to serovars 9 and 10 had low adherence at all time points.

Strong adherence was observed by scanning electron microscopy for the strains of serovars 5 and 4, which had high and moderate numbers, respectively, of H. parasuis cells attached to AOC-45 cells after 240 minutes of incubation.

The highest invasiveness was reached at 180 min by the serovar 4 strain, followed by the serovar 5 strain at 240 minutes. The invasion results differed substantially depending on the strain.

The researchers concluded that reference strains of H. parasuis serovars 1, 2, 4 and 5 exhibited high adhesion and invasion levels to AOC-45 porcine aorta endothelial cells, and these findings could aid to better explain the pathogenesis of the disease caused by these serovars.

Reference

^{Frandoloso R., M. Pivato, S. Martínez-Martínez, E.F. Rodríguez-Ferri, L.C. Kreutz and C.B. Gutiérrez Martín. 2013. Differences in Haemophilus parasuis adherence to and invasion of AOC-45 porcine aorta endothelial cells. BMC Veterinary Research. 9:207 doi:10.1186/1746-6148-9-207}

November 2013