Physiological effects of the lipopolysaccharide of Vibrio vulnificus on mice and rats.

Vibrio vulnificus is a pathogenic, marine, Gram-negative bacterium which commonly enters and infects humans via open wounds or the ingestion of raw seafood. The lipopolysaccharide (LPS) of V. vulnificus has recently been characterized, but the biological activity of this putative endotoxin is unknown. Three treatment groups were used to test its activity: saline (negative control), the LPS of Salmonella typhimurium (a known endotoxin), and the LPS of V. vulnificus. Whereas, intravenous injections of the S. typhimurium LPS caused mortality in two strains of mice, V. vulnificus LPS was not lethal. However, intraperitoneal injections into rats of both V. vulnificus and S. typhimurium LPS were pyrogenic. Intravenous injections of V. vulnificus LPS in rats caused decreased mean arterial pressure within 10 min which further declined, leading to death in 30 to 60 min. S. typhimurium LPS caused similar responses at the same concentration. The data suggest that the LPS of V. vulnificus may be a factor contributing to the virulence of this organism.