Detection of sea, sec and seq genes in Staphylococcus aureus nasal sampling acquiring from healthy carrier

Various assays have been used to identify of enterotoxins produced by Staphylococcus aureus and because of antigenic similarities among enterotoxins, serological assay may not always be practical. The aim of this study was to detect of S. aureus enterotoxins (SEA, SEC and SEQ) genes by multiplex PCR assay. Of 150 strains obtained from nasal carriers, 95 S. aureus were confirmed by biochemical test. Multiplex PCR assay for the detection of genes encoding staphylococcal enterotoxins A, C and Q genes (sea, c and q) S. aureus was used. The nuc gene, which encodes thermonuclease was used as a target DNA to identify S. aureus. DNA amplification fragments for the staphylococcal nuclease gene (nuc) was 397 bp, 552 bp for staphylococcal enterotoxin A gene (sea), 271 bp for staphylococcal enterotoxin C gene (sec) and 122 bp for staphylococcal enterotoxin Q gene (seq). S. epidermidis used as negative control and did not yield a PCR product. Among the 95 healthy human isolates from nasal carriage, forty one isolates (43/1%) were diagnosed as sea, sec or seq-positive. Twenty four (25/3%) isolates were sea gene, nine (9/5%) isolates were the sec gene and eight (8/4%) isolates were the seq gene and 54 (56/8%) of them were other se genes. Because Staphylococcus aureus was isolated in nasal healthy carrier, so the PCR assay could be useful in the routine direct detection of staphylococcal enterotoxin A, C and Q genes.