Toxigenic Escherichia coli Associated with Sudden Infant Death Syndrome

Abstract

The role of Escherichia coli as a cause of sudden infant death syndrome was investigated prospectively. Strains of E. coli producing the heat labile enterotoxin (LT) or the Vero-cell cytotoxin (VT) were isolated from the intestinal contents of 21/46 infants who died from sudden infant death syndrome (SIDS). None were found in the contemporaneously sampled faeces of 24 normal live infants in the same area. Live infants were used as controls in the absence of dead infants who had not died of SIDS. This high incidence of toxigenic E. coli among the SIDS infants versus the low incidence in controls, together with the general rarity of finding such toxigenic E. coli in the community of a temperate developed country, made us conclude that there may be a causal relationship between toxigenic E. coli and SIDS. The O and H serotypes of the toxigenic E. coli associated with SIDS infants tended not to be those normally considered to be toxigenic. The toxigenicity appeared to be relatively labile. It is suggested that SIDS may be associated with the infant either acquiring these unusual types of E. coli or more likely that its normal resident E. coli acquire the plasmids to produce these toxins.

Bacterial flora of Tasmanian SIDS infants with special reference to pathogenic strains ofEscherichia coli

“…Our survey of Tasmanian SIDS cases revealed TEC in 39 % of SIDS cases and in 1P5 % of comparison cases. The majority of these strains were observed to be either Verocytotoxin (VT) or Heat-labile toxin (LT) producers, similar to TEC isolated by Bettelheim and colleagues [18,19]. The serotypes obtained by Bettelheim and colleagues [18,19] were also not usually associated with toxigenicity in E. coli.…”

“…Investigations by Bettelheim and colleagues [18,19] and Luke and co-workers [20] indicated an alarmingly high prevalence of TEC from SIDS cases in South Australia and Victoria. Our survey of Tasmanian SIDS cases revealed TEC in 39 % of SIDS cases and in 1P5 % of comparison cases.…”

“…The Vero cell line was maintained as described by Bettelheim and colleagues [18]. Cytopathic effects were scored semiquantitatively on the basis of percent cell rounding; 50 % or greater cell rounding was regarded as positive [18].…”

“…Cytopathic effects were scored semiquantitatively on the basis of percent cell rounding; 50 % or greater cell rounding was regarded as positive [18]. All FVT extracts were kept and stored at -80 'C.…”

“…More specifically, during a pilot study by Bettelheim and colleagues [18] a strong association between heat labile enterotoxins (LT) and Verocytotoxin (VT) producing E. coli and SIDS was noted. Bettelheim and colleagues [18,19] found toxigenic E. coli (TEC) producers of LT or VT in 46 % of SIDS cases in South Australia, and this increased to 63 % from an examination of Victorian cases [20]. By contrast, no TEC were found in comparison non-SIDS infants of South Australia, whilst 22 % of such comparison infants in Victoria possessed these strains.…”