Detection of enterotoxin DNA in Staphylococcus aureus strains obtained from the middle meatus in controls and nasal polyp patients.

Background: Recent findings indicate that Staphylococcus aureus and its products may be involved in the modification of nasal polyposis. The purpose of this study was to investigate the presence of S. aureus enterotoxin genes and the agr subtype in bacterial DNA of S. aureus strains isolated from the middle meatus of nasal polyp and control patients.

Methods: S. aureus strains were isolated from nasal polyp patients and controls. The strains were screened using PCR for their agr subtype, classic superantigens (SEA, SEB, SEC, SED or TSST-1), the egc cluster (SEG, SEI, SEM, SEN, and SEO and other enterotoxins (SEE, SEH, SEJ, SEK, and SEL) distinct from the egc locus.

Results: Seventy-five percent of S. aureus strains had at least one enterotoxin in their DNA. The egc gene cluster was identified in 27 (67.5%) strains. At least one classic enterotoxin gene was present in 42.5% of the strains. Interestingly, there were no differences in enterotoxin genes between S. aureus strains isolated from controls compared with nasal polyposis patients. In controls, an equal distribution among the four agr groups was found, while 73% of the NPs strains belonged to agr groups I and II.

Conclusion: In this study we found no significant difference between strains from nasal polyp patients and controls in the presence of enterotoxin genes. However, in NPs, a higher number of strains belonged to agr I or II, which are associated with strains causing enterotoxin-mediated disease.