Isolation of Staphylococcus aureus and Shigella spp. from Thawed Fish

Abstract

Fish is a vital food source for people and contributes about 60% of the world's supply of protein. It is extremely perishable, and if not properly preserved, it deteriorates and can be detrimental to human health when consumed. The present study was carried out to isolate Staphylococcus aureus and Shigella spp. from thawed fish. A total of 10 thawed fish samples were bought from different fish retailers in different markets within Enugu metropolis. The result revealed that out of the 10 thawed fish samples that were analyzed using Mannitol Salt Agar and Salmonella Shigella Agar, 8(80%) of the samples had Staphylococcus aureus while 6(60%) had Shigella spp. The isolates were subjected to different antibiotics, and the result showed that all the Staphylococcus aureus isolates were sensitive to Amoxicillin and ciprofloxacin. Also, 7 isolates were sensitive to Erythromycin and Rifampicin, while 6 isolates were sensitive to Levofloxacin, and 4 isolates were sensitive to Ampiclox and Norofloxacin. All the Staphylococcus aureus isolates were resistant to chloramphenicol, while 6 isolates were also resistant to Gentamycin, and 7 isolates showed resistance to Streptomycin. Also, all the Shigella spp. isolates were sensitive to Ciprofloxacin, Amoxicillin, and Perfloxacin. 5 isolates were sensitive to Augmentin, while 4 isolates were also sensitive to Streptomycin and Gentamycin. All the isolates were resistant to chloramphenicol and Septrin. The study shows that the thawed fish samples may have been contaminated through faecally contaminated water bodies and through unhygienic handling of the fish during and after harvest. Hence, it is important to find better ways of preserving/handling fish to avoid contamination with pathogenic micro-organisms since it can be detrimental to human health.