Prevalence of SEA and SEB producing Staphylococcus aureus isolated from foodborne- outbreaks in Iran

Staphylococcus aureus is an important pathogen causing a wide variety of diseases such as skin infections, food poisoning, pneumonia and septicemia in humans and animals. Among the bacterial agents of food poisoning, S. aureus is the most common agent worldwide. The aim of this study was to assess prevalence of SEA, SEB enterotoxin producing S. aureus isolated from foodborne outbreaks in Iran. In this study, 313 diarrheal samples from 120 outbreaks were collected from December 2017 to August 2018. Isolates were identified using classical methods. The antimicrobial resistance patterns of the S. aureus isolates were assessed using standard disk-diffusion and E-test methods. Presence of sea and seb genes was investigated using polymerase chain reaction (PCR). Data were analyzed using SPSS and Excel Software as well as statistical tests. In this study, 55 samples (17.6%) from an overall number of 313 samples from food outbreaks were identified as S. aureus, which were assessed for their antimicrobial susceptibility. The highest contamination belonged to Yazd (50.9%) and Semnan (29.1%) Provinces. However, no contaminations of S. aureus were seen in Zanjan Province. The S. aureus was more common in females (50.9%) than males. Furthermore, S. aureus isolates were mostly resistant to penicillin (81.8%) and completely susceptibile to vancomycin. Of 55 isolates of S. aureus, four isolates (7.3%) were positive for sea and one (1.8%) for seb genes. The current study has shown that S. aureus food infection is one of the most common foodborne diseases, caused by the ingestion of staphylococcal enterotoxins produced by enterotoxigenic strains of staphylococci. Therefore, further screening and monitoring programs are suggested for the prevention of staphylococcal infections.