Mouse Skin Damage Caused by Cytolysin from Vibrio vulniflcus and by V. vulnificus Infection

Light and electron microscopy of mouse skin damage caused by intradermal infection with a virulent strain of Vibrio vulnificus and by a single intradermal injection of the cytolytic toxin produced by the bacterium revealed similar structural alterations. The epidermis was intact; however, the infection and toxin produced acute cellulitis characterized by (I) extensive extracellular edema; (2) disorganization of collagen bundles; (3) large accumulations of cell debris and plasma proteins; (4) damaged or necrotic fat cells, capillary endothelial cells, and muscle cells; and (5) mild inflammatory cell infiltration. The virulent strain of V. vulnificus produced a capsule and was resistant to phagocytosis in vivo, whereas a weakly virulent strain of the bacterium did not produce a capsule and was readily phagocytized and digested. Factors that may be important in the pathogenesis of V. vulnificus wound infections include a capsule that inhibits phagocytosis and an extracellular cytolytic toxin that is responsible, at least in part, for the severe tissue damage characteristic of such wound infections.