• Classical Enterotoxin Genes Investigation of Staphylococcus aureus Isolated from Urine Clinical Sample using Molecular Technique
  • Ghazale Faridfar,1 Mohammadreza Akbari,2,* Shahin Faridfar,3 Amin Nourian,4
    1. Islamic Azad University, Tehran Medical Sciences Branch, Faculty of Sciences & Technology, Tehran, Iran.
    2. Biology Science and Technology Center, Faculty and Research Institute of Basic Science, Imam Hossein Comprehensive University, Tehran, Iran
    3. Biology Science and Technology Center, Faculty and Research Institute of Basic Science, Imam Hossein Comprehensive University, Tehran, Iran
    4. Biology Science and Technology Center, Faculty and Research Institute of Basic Science, Imam Hossein Comprehensive University, Tehran, Iran


  • Introduction: Staphylococcus aureus is an important pathogen of humans in nosocomial and non-nosocomial infections. These bacteria can produce several extracellular toxins. Staphylococcal enterotoxins (SEs) are the common notable virulence factors in these bacteria. Classical SEs classified into 5 serological types (SEA to SEE) based on their antigenicity. The genes encoding the enterotoxins are often on a variety of distinct mobile genetic elements. Hence, the distribution of enterotoxins can vary broadly among various S. aureus isolates. Accordingly, an annual-long update of data on the prevalence of S. aureus and its enterotoxins (SEs) genes improves the analysis, prevention, and treatment plans in every region. So, the presence of enterotoxin genes in S. aureus strains isolated was evaluated from the clinical sample by the molecular technique.
  • Methods: In this study, we analyzed random urine samples obtained from clinical specimens for tracking of S. aureus strains through the traditional procedure. Next, isolates were evaluated for the presence of toxin-producing genes (A-E) using Polymerase Chain Reaction (PCR) assay. Finally, the highest frequencies of isolates containing classical enterotoxin gene (SEs) were reported.
  • Results: In this scheme, a total of 50clinical urine samples suspected of staphylococcus were elected, which the S. aureus was confirmed utilizing the conventional method in 36 of them. Following bacteriological methods, 36 isolates were gram-positive and beta-hemolytic. The effect of the mannitol salt agar, catalase, and tube coagulase assays was also approved for them. The results of the molecular technique demonstrated 17 cases were positive only for one type of SEs (SEA) while the remaining samples were negative. None of the isolates were also positive for SEs (B, C, D, E). Consequently, the results showed the meaningful presence of the genes encoding staphylococcal enterotoxin A (SEA) in most isolated strains.
  • Conclusion: The outcome of this study revealed that most S. aureus strains isolated from urine samples produced SEA compared to other SEs. This means most presumably of the staphylococcal strains approved using the PCR technique were enterotoxigenic. We found probable evidence that the SEA gene plays an important part in infectious staphylococcal genomes. Accordingly, the relatively high prevalence of the enterotoxins A(SEA) gene in the isolates indicated the potential of these bacteria to cause urinary infection. In general, information from this study has provided a reliable understanding of S. aureus spread in the clinical infection diseases that reflects the current poor control of these bacteria.
  • Keywords: Classical Enterotoxin; Polymerase Chain Reaction; Staphylococcus aureus; Enterotoxin A.