Prevalence and characterization of Staphylococcus aureus in fresh indian mackerel (Rastrelliger kanagurta) in Unguja island
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Date
2017
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Publisher
Sokoine University of Agriculture
Abstract
A cross-sectional study design was conducted to assess the prevalence and characterization of Staphylococcus aureus in fresh Indian mackerel fish (IMF) in Unguja Island. A total of 400 fish samples of IMF were collected from three landing sites Malindi, Mangapwani and Mkokotoni. From each fish two samples were collected namely fish skin swab and fish tissue (muscle). The primary culture were obtained from Mannitol salt agar, Nutrient and Blood agar followed by Gram staining, Catalase, Coagulase (slide and tube) tests. The DNA from the representative isolates was extracted using boiling method. DNA fragments were amplified from isolated DNA based on 16S rRNA, nuc, mecA, pvl, spa and enterotoxins genes depending on specific primers. The PCR products were detected by agarose gel electrophoresis. The results indicated that growth of bacteria from fish skin swabs were 359 (89.75%) and fish tissue were 102 (25.5%). Based on biochemical tests, 27 isolates (6.75%) were confirmed to be Staphylococcus bacteria. Of the 27 isolates, seven (1.75%) were confirmed S. aureus based on PCR results. All twenty seven isolates confirmed to be positive in16S rRNA gene, two isolates demonstrated mecA gene and one had enterotoxins SEB and SEC. The SEA, spa and pvl genes were not detected. In conclusion, the prevalence of S. aureus was rather low (1.75%), but this has an implication in public health to community using IMF. This will lead to incidences of food borne diseases caused by S. aureus. Therefore, data presented here are useful for risk assessment and management of pathogenic S. aureus in IMF.
Description
Master's degree Dissertation
Keywords
Staphylococcus aureus, Rastrelliger kanagurta, Unguja Island, Staphylococcus aureus characterisation, Indian mackerel fish