ENTEROTOXIGENIC BACTERIA IN THE SUDDEN-INFANT-DEATH-SYNDROME

Faecal samples from 123 infants who died with sudden infant death synd rome (SIDS) and from a comparative group of 52 age-matched babies were analysed for toxigenic bacteria and their toxins. Serum samples from the SIDS infants were also analysed for these toxins. A significantly higher proportion of toxigenic bacteria and their toxins were found in faecal samples of SIDS babies than in samples from the comparative gr oup. These toxins were also found in serum from the SIDS babies. Clost ridium perfringens was found in 54 (45.4%) of 119 SIDS cases compared with 10 (19.6%) of 51 healthy babies (chi2 = 10.1, p < 0.01); C. diffi cile in 33 (27.7%) of 119 SIDS cases compared with 8 (14.8%) of 54 hea lthy babies (chi2 = 3.43ns, p < 0.1); Staphylococcus aureus in 12 (27. 3%; 66.7% enterotoxigenic) of 44 SIDS cases compared with 12 (85.7%; n on-enterotoxigenic) of 14 healthy babies (chi2 = 14.9, p < 0.001); C. botulinum in 6 (5.0%) of 120 SIDS cases compared with 0 of 53 healthy babies (chi2 = 2.74, p < 0.1). Campylobacter jejuni, Yersinia enteroco litica, Vibrio parahaemolyticus, salmonellae and Bacillus cereus were not detected. Heat-labile toxin, lethal to mice (HLML) was found in 32 (27.1%) of 118 SIDS faecal samples compared with 5 (10.6%) of 47 heal thy babies (chi2 = 5.24, p < 0.05); cytotoxins in 38 (30.9%) of 123 SI DS faecal samples compared with 0 of 21 of healthy babies (chi2 = 8.8, p < 0.01) and 24 (27.6%) of 87 SIDS serum samples. C. perfringens ent erotoxin was detected in 33 (34.4%) of 96 SIDS faecal extracts compare d with 0 of 23 of healthy babies (chi2 = 10.94, p < 0.001), and in 27 (24.5%) of 110 SIDS serum samples. C. perfringens alpha-toxin (presump tive) was detected in 14 (17.5%) of 80 SIDS faecal extracts compared w ith 0 of 17 from healthy babies (chi2 = 3.5ns, p is equivalent to 0.05 ) and in 2 (2.3%) of 87 SIDS serum samples. C. difficile toxin was det ected in four SIDS faecal samples and two serum samples. C. botulinum toxin was detected in only one of 120 SIDS faecal samples compared wit h none of 49 from healthy babies. Staphylococcal enterotoxins were det ected in 8 (19.5%) of 41 SIDS faecal samples compared with 0 of 19 fro m healthy babies (chi2 = 4.278, p < 0.05), and in 4 (10.8%) of 37 SIDS serum samples. Toxigenic and non-toxigenic strains of C. perfringens and C. difficile occurred in faecal samples of both SIDS and healthy b abies. Formula-fed SIDS babies had a significantly higher incidence of C. difficile (chi2 = 6.654, p < 0.01), C. perfringens (chi2 = 6.422, p < 0.05), and its enterotoxin (chi2 = 7.787, p < 0.01) in faeces, and a higher incidence (non-significant) of C. perfringens enterotoxin in their serum, faecal HLML toxin, and S. aureus and its enterotoxin, th an breast-fed babies. Male SIDS babies had a significantly higher inci dence of C. perfringens (chi2 = 7.687, p < 0.01) and higher incidences (non-significant) of C. perfringens enterotoxin, HLML toxin, C. diffi cile, and S. aureus and its enterotoxin than female babies. SIDS babie s dying in winter had a significantly higher incidence of C. difficile than those dying in summer (chi2 = 5.328, p < 0.05) and spring (chi2 = 4.444, p < 0.05). C. perfringens, S. aureus and their enterotoxins o ccurred in more babies dying in autumn and winter than in spring and s ummer. The incidence of these bacteria and their toxins did not differ for position of death. These results provide some support for the ide a that intestinal toxins have a pathogenic role in SIDS.