Intense exercise stress may trigger Corynebacterium kutscheri infection in Sprague-Dawley rats

Abstract

In this study, Corynebacterium kutscheri infection was reported in Sprague-Dawley rats that were stressed due to intense exercise during an experimental study. Weight loss, indifference to the environment, fluffy feathers, and hunched posture were observed in affected rats. The lungs contained numerous, randomly distributed, variably sized, slightly raised, cream-colored caseopurulent foci. There were occasional weak adhesions between the lung lobes and the adjacent costal pleura. Multifocal to coalescing necro-suppurative pneumonia with intralesional scattered large colonies of bacteria was observed histopathologically. Adjacent in the pulmonary parenchyma, interalveolar hypercellularity, type II pneumocyte hyperplasia, fibrinonecrotic vasculitis, and pleuritis were observed. Brown-Breen staining revealed gram-positive cocobacilli in the lesion areas. Furthermore, cardiac lesions in which the atria were more severely affected than the ventricles were identified. This lesion was characterized by thickening of the epicardium with intense infiltrates of macrophages admixed with scattered neutrophils. In severely affected rats, this lesion was also involved to the underlying myocardium. Bacterial culture yielded positive growth for C. kutsheri from the lesioned organ. Polymerase chain reaction was used to confirm the presence of genetic material for C. kutscheri. As a result, it was revealed that Sprague-Dawley rats were infected with C. kutscheri due to intense exercise stress. Periodic controls of C. kutscheri have been suggested in units where experimental animals are raised, both because of its negative effects on the results of the studies to be conducted and because of its zoonotic nature.