Intestinal infection and toxin production by Clostridium botulinum as one cause of sudden infant death syndrome.

The spontaneous production of botulinum toxin in the infant gut by ingested Clostridium botulinum organisms is the underlying cause of infant botulism, recognised as an infectious disease only in late 1976. Because of the recognition of the pathophysiology of this disease and because the known potency and action of botulinum toxin can lead to rapid respiratory arrest, it appeared possible that the in-vivo production of botulinum toxin could cause the sudden death of some infants. To test this hypothesis, serum, selected tissues, and bowel contents from 280 dead infants were examined for the presence of C. botulinum toxin and/or organsisms. We found C. botulinum organisms in 10 infants, all of whom died suddenly and unexpectedly. 9 of these deaths were classified by the forensic pathologist as sudden infant death syndrome (S.I.D.S. or crib death). In 2 of these 10 sudden deaths both C. botulinum organisms and botulinum toxin were identified, and from the spleen of 1, C. botulinum organisms were isolated. Faecal specimens from 160 age-matched healthy infants who served as controls in studies of inpatient infant botulism cases were negative for both C. botulinum organisms and toxin, except for one specimen that contained only C. botulinum type A organisms. The 9 S.I.D.S. cases with evidence of C. botulinum infection comprised 4.3% of the 211 S.I.D.S. cases examined over 12 months. These findings suggest that intestinal production of botulinum toxin by C. botulinum is one cause of S.I.D.S. The strikingly similar age-distribution of 62 inpatient infant botulism cases and the 211 S.I.D.S. cases is also consistent with this concept. The possibility that in-vivo production of botulinum toxin may account for a larger proportion of S.I.D.S. cases is discussed.