Because of the significance of Staphylococcus aureus strains in nosocomial infections and the role of enterotoxins as superantigens in various diseases, in the present study we evaluated the sea and nuc genes that encoding enterotoxin in Staphylococcus aureus isolates, isolated from Nasal mucosa of staff in Sari burn hospital by PCR method. According to the results, all 20 positive samples had nuc nuclease gene, and 6 (30%) of 20 Staphylococcus aureus positive samples had sea gene.
In a study by Asgarpoor et al. among the 136 nasal swab samples, 46 (33.8%) were positive for S. aureus, and from 46 isolates, the sea, seb and sec genes were found in 11 (23.9%), 6 (13%) and 5 (10.8%) isolates, respectively . In Rall et al. study 82 nasal and hand swabs were evaluated in food handlers and found that the most common gene was sea (35.4%), followed by seh and sej (29.2%) . Amini et al. evaluated the Staphylococcus aureus enterotoxin genes using multiplex PCR in 60 clinical samples and showed that 50% of Staphylococcus aureus samples contained the enterotoxin gene. The most frequent gene was sea (30%) and sed (10%), see (3.8%), and sec respectively . In da Silva et al work, out of 58 Staphylococcus spp. 29 (50%) were positive for one or more enterotoxin genes, and the main genes were seg and sei (29.3%) . In a study by Udo et al. in Kuwait, samples of nasal swabs, feces, and hands of 250 restaurant employees were evaluated to detect staphylococcal enterotoxin genes. From 200 isolates of Staphylococcus aureus isolated from people working in restaurants, the frequency of sea, seb, and sec genes were reported to be 11%, 12.5% , and 23%, respectively . Peck et al. study in Korea showed that sea gene was the most abundant among enterotoxin genes and out of 95 strains of Staphylococcus aureus isolated from the nose of individuals, 47.4% carried this gene . In the study of Saadati et al., from 95 strains of Staphylococcus aureus isolated from the noses of carriers, the frequency of sea, seb, and sec genes were 25.3%, 15.8%, and 9.5%, respectively .
Due to differences in sample size, geographical location, the race of individuals, and level of personal and general health, the frequency pattern of Staphylococcus aureus vectors are different. It seems that Staphylococcus aureus strains isolated in the above studies have different enterotoxinizing power and this important issue is also effective in increasing or decreasing the pathogenicity of this bacterium. It can be said that the location of bacterial colonization can affect the frequency of enterotoxigenic Staphylococcus aureus.