Experimental staphylococcal endocarditis in pigs: Bacteriological, histopathological and scanning electron microscopic observations

Abstract

Septicaemia and lesions of endocarditis and arthritis were caused in a proportion of conventional and gnotobiotic pigs inoculated with a strain of Staphylococcus aureus isolated from a spontaneously occurring staphylococcal endocarditis in a pig. Staph. aureus could, in most cases, be isolated from the infected heart valves, but only in rare instances from the affected joints. The lesions of arthritis occurred more often than the endocardial lesions in the conventional pigs. Selected tissues from the heart of the infected animals were specially prepared and examined with the light microscope (LM) in conjunction with a scanning electron microscope (SEM). This method made it possible to derive more information about the pathological changes than by light microscopy alone. Frequently the lesions in the myocardium were not detected with the LM, but were more readily detected with the SEM. It is suggested that the SEM could prove a useful tool in diagnostic pathology, especially when its image can be correlated with the LM.