الخلاصة

Abstract: Objectives: The present study was planned for detection of the frequency of genes that is responsible for enterotoxin excretion in S. aureus isolated from dermal lesions of atopic dermatitis (AD) cases in AL-Najaf city, and to evaluate the single and combined existence of enterotoxins coding genes. Methodology: A total of 54 Staphylococcus aureus isolates were applied to polymerase chain reaction specific for the amplification of various genes coding for Staphylococcal enterotoxins including 3 types (sea,seb and sec) with two sets each. Results: As a result of DNA extraction and polymerase chain reaction directed to amplify the specific enterotoxin coding genes; The seb-6 gene was the most frequent gene , since it was detected in average of 8:36(22.22%), followed by the two sets of sec (sec-11 and sec-15) genes that comprised an equal average of 7:36(19.44%) each. Sea-2 gene set was detected in 6:36 (16.7%) , while the lowest detection was seen for sea-1 and seb-7 since they were detected in 4:36(11.1%)each. Our results showed that single frequency was comprised 23:36 (63.9 %), while the combined frequency was detected in 13:36(36.1%). The most frequent enterotoxin coding genes as a combined were sec-15 (19.44%), sea-2 (8.3%). Most single existence of replicated gene was detected for seb-6 and sec-11 (19.44%) and (16.7%) respectively. Our results showed that absolutely single frequency was related to sea-1 gene(11.11%), while the absolutely combined frequency was seen in sec-15 (19.44%). Conclusions: Polymerase chain reaction and use of designed primers are important technique for the detection of Staphylococcus aureus enterotoxins (A, B and C), and seb-6 gene was the most frequent gene. Key words: Multiplex PCR, S.aureus, primers, atopic dermatitis