Cytopathic effects in MDBK cell lines after adhesion and internalization of Corynebacterium pseudotuberculosis biovar ovis.

Abstract

Caseous lymphadenitis is a contagious disease of chronic evolution affecting mainly sheep, goats, and other domestic animals. The virulence of its etiological agent, Corynebacterium pseudotuberculosis, depends on the activity of enzymes, such as phospholipase D, and its waxy lipid mycolic acid layer, which induces cytotoxicity on the tissue cells of the host. Phospholipase D and mycolic acids contribute to inflammation, edema, and bacterium spread during abscess development. Here, we assessed the adhesion and internalization capacity of six isolates of C. pseudotuberculosis biovar ovis in a non-phagocytic cell lines (Madin-Darb Bovine Kidney (MDBK)) and the cytopathic effects produced in these cells. The interaction of the bacteria strains with MDBK as assessed through scanning electron microscopy and, their cytopathic effects was analyzed by Giemsa staining under light microscopy. Both microscopy assays were monitored after 6, 24, and 72 h of infection. The cytopathic effects evaluated were the formation of cytoplasmic vacuoles, alteration in the nucleus/cytoplasm ratio, and cell lysis. C. pseudotuberculosis biovar ovis was able to adhere and invade MDBK and remained viable for up to 72 h in the cell culture while inducing different levels of cytopathic effects.