Staphylococcus aureus and Salted Fish: Prevalence, Antibiogram, and Detection of Enterotoxin-coding Genes

This study was taken to investigate the prevalence of Staphylococcus aureus (S. aureus) in four types of salted fish, namely salted sardine, fesiekh, sahlia, and salted herrings that retailed in Zagazig city, Egypt. The antimicrobial susceptibility testing of the recovered S. aureus isolates was examined. Moreover, PCR was used for the detection of the coding genes of S. aureus-enterotoxins (SE) including SEA, SEB, SEC, and SED. The obtained results of the current investigation revealed isolation of S. aureus from the examined salted sardine, fesiekh, sahlia, and salted herrings at 15%, 40%, 30%, and 15%, respectively. Fesiekh had significantly (p< 0.05) the highest total S. aureus count (3.17 ± 0.13 log 10 cfu/g), followed by sahlia (3.08 ± 0.13 log 10 cfu/g), sardine (2.33 ± 0.07 log 10 cfu/mL), and salted herrings (2.30 ± 0.11 log 10 cfu/g), respectively. Besides, 10%, 35%, 20%, and 5% of the examined salted sardine, fesiekh, sahlia, and salted herrings, respectively exceeded Egyptian limits of S. aureus. The recovered S. aureus isolates showed clear multidrug resistance profiling. PCR testing of selected S. aureus isolates for harboring Staphylococcal enterotoxin-coding genes revealed SEA, and SEB were not detected in any examined isolate. However, SEC was detected in 3 S. aureus isolates recovered from fesiekh, and in 2 isolates that recovered from sahlia. SED was only detected in 2 isolates that recovered from fesiekh. Therefore, strict hygienic measures should be adopted during handling, and processing of salted fish.