Staphylococcal enterotoxin genes are common in Staphylococcus aureus intestinal flora in Sudden Infant Death Syndrome (SIDS) and live comparison infants

Abstract

Pathological and epidemiological findings in sudden infant death syndrome (SIDS) suggest an infectious aetiology with indications of involvement of staphylococcal enterotoxins (SEs). While SEA, SEB and SEC have been found in the sera and tissues of SIDS cases, little is known about the role of intestinal Staphylococcus aureus or the roles of later-described toxins SEE, SEG, SEH, SEI and SEJ in SIDS. We used a molecular-based approach to define whether the intestinal tract could be a source of SEs to support the staphylococcal toxic shock hypothesis for SIDS. Intestinal contents from 57 SIDS infants and faeces from 79 age- and gender-matched live comparison infants were cultured and tested for S. aureus and sea-b-c-e-g-h-j and TSST using PCR. High proportions of infants in both groups carried toxigenic and nontoxigenic S. aureus. Significantly greater proportions of SIDS compared with comparison babies were positive for S. aureus (68.4% vs. 40.5%) and for SE genes (43.8% vs. 21.5%), suggesting a possible role in SIDS. The results indicate that colonization by S. aureus with SE genes is common in infants; however, their detection is unlikely to be a strong predictive tool for SIDS. Other factors (including immune response) may reveal a specific susceptibility to SEs in SIDS infants.