Morphology of sulfur granules produced by Staphylococcus aureus and Corynebacterium pyogenes in cows

Sulfur granules produced by Staphylococcus aureus and Corynebacterium pyogenes were studied by light and electron microscopy. They consisted of bacteria and electron-dense amorphous substance which formed clubs in the periphery of each granule. In those produced by Staph. aureus, cocci were seen at the center of each granule. They were round or pleomorphic. Binary fission was frequently observed. In those produced by Coryn. pyogenes, degenerative bacteria were present at the center of each club. Bacteria found just beneath the club had a thick, electron-less-dense cell wall and electron-dense cytoplasm. Those present at the center of the granule were very long and had a cell wall thin and sometimes undulant, containing ribosomes. The electron-dense amorphous substance surrounded these bacteria and faced the neutrophils or epithelioid cells in the periphery of the granule both species of organisms. They might have been produced by bacteria. Cellular reactions of neutrophils, epithelioid cells, fibroblasts and plasma cells were seen around the sulfur granules produced by both species of organisms.