Isolation of Clostridium botulinum type G and identification of type G botulinal toxin in humans: report of five sudden unexpected deaths.

Clostridium botulinum type G has not been identified until now from humans or animals; it has been isolated only twice, from soil samples in Argentina. Type G organisms were isolated from necropsy specimens in four adults and an 18-week-old infant. Type G botulinal toxin was demonstrated in the serum of three of these individuals. The toxic dose in mice ranged from 2 to 7 50% lethal doses/ml. These persons died suddenly and unexpectedly at home, without any pathologic evidence to account for the cause of death in four cases. Symptoms in two individuals were similar to those observed in food-borne botulism. Thus, a prompt postmortem search for toxin and organisms of C. Botulinum in blood and feces may be worthwhile in determining the etiology of unexplained deaths. More microbiologic, physiologic, and toxicologic data are needed to clarify the role of C. botulinum in the pathogenesis of sudden unexpected death in infants and adults.