Isolation and identification of Staphylococcus aureus from meat products and detection of SEA producing gene in food samples related to poisoning

BACKGROUND AND OBJECTIVES Background and purpose: Staphylococcus aureus is known as one of the most common causes of food poisoning in many countries. This bacterium has many toxins, among which enterotoxin is more important, and consuming foods contaminated with this toxin causes food poisoning. Staphylococcal enterotoxins (SEs) are single-chain extracellular proteins with low molecular weight (۲۲-۲۹ kDa) that are similar in terms of biological activity but different in terms of antigens. These toxins have ۲۳ different types that cause nausea, vomiting, diarrhea, muscle and abdominal pain, and sometimes lead to death. The purpose of this study is to review the role and importance of Staphylococcus aureus enterotoxins in food poisoning, pathogenesis, laboratory methods of purification and detection of these toxins.MATERIALS AND METHODSBy collecting more than ۱۰۰ meat samples, the samples were examined for the presence of Staphylococcus aureus using standard culture techniques and standard phenotyping tests. After extracting DNA by authentic internal kits and designing specific primers and using the standard strain of Staphylococcus to identify the sea gene, a rapid PCR test with high specificity was performed. Based on the obtained results, Staphylococcus aureus was isolated in ۱۹ samples (۱۲.۶%). The highest level of contamination was related to smoked fish (۳۰%) and the lowest level of contamination was related to chicken schnitzel (۳%), but no cases of Staphylococcus aureus contamination were observed in sausages. Staphylococcus aureus was counted using Bradparker agar medium. In the following, the frequency of genes of enterotoxins A-H and I, H, G and pseudo-J has been evaluated by PCR technique.RESULTS AND DISCUSSION۶۸% of the samples were infected with Staphylococcus aureus. The average number in raw and cooked minced meat samples, respectively, was equal to ۱.۳ x ۱۰۵ g/cfu and ۵.۷ x ۱۰۳ g/cfu, and among ۹۲ isolates, ۲۳ isolates, i.e. ۲۵%, carried coding genes. They were enterotoxins. Of the above ۲۳ isolates, ۱۵ isolates (۶۵.۲%) carried one enterotoxin gene and the rest carried۴۸۲more than one gene. So that two isolates had SEA and SEC genes, two isolates carried SEA and SEE genes, one isolate carried SEA and SEG genes, one isolate carried SEC and SEI genes, one isolate carried SEC, SEA and SEG genes and one isolate carried SEE and SEG genes. Statistical investigations showed that there is a statistically significant difference in the comparison of the frequency of Staphylococcus aureus and the type of meat products. (p<۰.۰۵. Rosec and his colleague Gigaud in ۲۰۰۱ in France, a study with the aim of identifying Genes of classical staphylococcal enterotoxins Enterotoxins and (see and sea, seb, sec, sed) SEI, SEG, SEH and SEJ on ۱۵۹ food samplesVarious, including cheese, milk, raw and cooked meatPork, sweets, minced meat, ice cream and semolina. They made corn. ۳۳۲ of all examined samplesStaphylococcal strain isolation and accordingto the presence of genes Encoder of tested staphylococcal enterotoxinsThey decided They showed that ۵۷% of the strains haveStaphylococcal enterotoxin genes are often fromThe type of classic enterotoxins was staphylococci These are among the important researchand the role of Staphylococcus aureus enterotoxins inRefers to health and public health.CONCLUSIONthat the amount of food contamination with Staphylococcus aureus was relatively significant and due to the importance of Staphylococcus aureus in the production of various toxins and the most important cause of poisoning, due to the increasing consumption of ready-to-cookfoods, it threatens the public health.