A two-stage continuous culture system to study the effect of supplemental α-lactalbumin and glycomacropeptide on mixed cultures of human gut bacteria challenged with enteropathogenic Escherichia coli and Salmonella serotype Typhimurium

摘要

Aims: This paper reports on a new putative enterotoxin SEU encoded by the enterotoxin gene cluster egc from Staphylococcus aureus and on a real-time polymerase chain reaction (PCR) assay for detecting the sell gene. Methods and Results: PCR and sequencing revealed a new putative enterotoxin SEU encoded by some egc clusters. The sera gene resulted from sequence divergence in the ψ ent1 and ψ ent2 pseudogenes previously described in the egc cluster (Jarraud et al. [2001] Journal of Immunology 166, 669). The presence of the sell gene was investigated in a collection of S. aureus strains by conventional PCR and by a specific 5'-nuclease PCR assay. Among the 24 strains harbouring the egc cluster, four tested positive for the sell gene. Conclusions: The existence of the sell gene adds to the number of newly described se genes and underlines the need for a better understanding of their role in the pathogenesis of S. aureus. Significance and Impact of the Study: A thorough study of the sell gene should provide further insight into the phylogenetics of the staphylococcal enterotoxins.