PULMONARY DAMAGE BY VIBRIO-VULNIFICUS CYTOLYSIN

Vibrio vulnificus is an estuarine bacterium that causes septicemia and serious wound infection. Cytolysin produced by V. vulnificus has been incriminated as one of the important virulence determinants of bacter ial infection. Cytolysin (8 hemolytic units) given intravenously to mi ce via their tail veins caused severe hemoconcentration and lethality. Cytolysin treatment greatly increased pulmonary wet weight and vascul ar permeability as measured by I-125-labeled albumin leakage without a ffecting those factors of other organs significantly. Blood neutrophil s were markedly decreased in number after cytolysin injection, with a concomitant increase in the level of pulmonary myeloperoxidase activit y, indicating that cytolysin-induced neutropenia might be due to pulmo nary sequestration of neutrophils. By microscopic examination, severe perivascular edema and neutrophil infiltration were evident in lung ti ssues. These results suggest that increased vascular permeability and neutrophil sequestration in the lungs are important factors in lethal activity by cytolysin.