Staphylococcus aureus is one of the most common causes of seafood-borne diseases worldwide, which are attributable to the contamination of food by preformed enterotoxins. In this study, a total of 206 (34.3%) Staphylococcus aureus strains were obtained from 600 fish and shrimp samples and were tested for their antimicrobial susceptibility. We assessed the prevalence of the genes responsible for the staphylococcal enterotoxins (SEA, SEB) and toxic shock syndrome toxin 1 (TSST-1) genes. The results indicated that 34% of aqua food samples were contaminated with S. aureus, and 23.8% of these isolates were mec-A-positive. Sixty-four percent of the strains isolated from contaminated seafood was enterotoxigenic S. aureus, and 28.2% of SEs were MRSA-positive. The most prevalent genotype was characterized by the presence of the sea gene (45.2%), followed by the seb gene (18.5%), and the tst gene encoding TSST-1 was found in eight strains (3.9%). Of the 206 S. aureus isolates, 189 strains (84.9%) were resistant to at least one antibiotic. Given the frequent outbreaks of enterotoxigenic MRSA, it is necessary to make revisions to mandatory programmes to facilitate improved hygiene practices during fishing, aquaculture, processing, and sales to prevent the contamination of fishery products in Iran.

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Aquatic organisms are a source of organic compounds that hold various features such as medical and nutritional activities. Within the framework of an antimicrobial activity study of marine macro-organisms from the Persian Gulf, bioactive compounds of the sea cucumber Holothuria leucospilota were extracted from the whole body using chloroform and methanol. The extracts were evaluated for their antibacterial effects against methicillin-resistant (MRSA) and staphylococcal enterotoxins producing (SEA, SEB) Staphylococcus aureus strains. Activities have been determined using three methods: disk diffusion tests, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC). The results demonstrate that methanol and chloroform extracts have an inhibitory effect on the growth of all strains at MIC concentrations up to 100 mg/ml. Also, chloroform extracts demonstrate bactericidal activity against SEB in concentrations of about 100 mg/ml. The extracts also show bactericidal effects against MRSA and SEB below 100 mg/ml concentrations. The highest antibacterial activity was found in methanol extract. Therefore, sea cucumber extracts are good candidates for the identification of new antimicrobials. Yet, comprehensive investigations are needed to separate and identify the active components for Holothuria leucospilota from the Persian Gulf.

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