The bovine enterotoxaemia complex. Its aetiology, antibody response to vaccination and problems in diagnosis

The effect of enteric bacterial toxins on the catecholamine levels of the rabbit

The rabbit catecholamine responses to bacterial toxins commonly found in Sudden Infant Death Syndrome (SIDS) victims were studied as part of a proposed animal model for SIDS. Six bacterial toxins commonly isolated from SIDS baby feces and a comparison endotoxin were injected intravenously (i.v.) and intraluminarily (i.l.) to determine their effects on catecholamine levels. I.v. injected toxins clearly altered catecholamine levels causing sharp rises in adrenaline and noradrenaline levels and at critical toxin concentrations sudden death ensued. Clostridium perfringens enterotoxin and alpha-toxin, Clostridium difficile enterotoxin (A) and cytotoxin (B), Escherichia coli STa toxin and staphylococcal enterotoxin B caused rises in catecholamine levels similar to that caused by E. coli endotoxin. Control rabbits showed very little or no obvious change in catecholamine levels. Clostridium difficile enterotoxin (A) and cytotoxin (B) injected i.v. exhibited synergy. Toxins injected into the duodenum, jejunum, ileum, cecum and large intestine caused behavioural changes ranging from reduced appetite and diarrhea to, in rare cases, death. Changes in the catecholamine levels of these animals however were not significantly different from those of the control animals. The results are discussed in relation to the possible effect of certain conditions (physiological, viral infections and environmental) which increase toxin permeability and allow absorption of these toxins, possibly resulting in sudden infant death.