Video: Leukotoxic Streptococcus pyogenes

These Streptococci Kill White Cells

Although a neutrophil can kill this bead-like string of Streptococcus pyogenes, this particular strain of bacteria expresses streptolysin-s on its surface which kills the white cell through necrosis, a death in which the cell swells and eventually bursts. The white cell's lytic granules (lysosomes), which are supposed to fire their antibacterial contents onto the surface of the bacteria, are emptied into the white cell's cytoplasm instead, adding to the necrotic death. The granule contents also leak out of the cell through the damaged cell membrane releasing inflammatory products. Necrosis is very different from the more controlled cell death called apoptosis.