STUDIES ON THE INCIDENCE OF STAPHYLOCOCCUS AUREUS AND ITS TOXINS IN LIVESTOCK PRODUCTS
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Date
42644
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PVNR TVU
Abstract
The present study was undertaken to standardize PCR assay for detection of S.aureus and its toxins from livestock foods and compare its efficacy with conventional cultural methods. Primers derived from nuc, sea, seb and tst genes were used, which gave specific amplification products of 279, 120, 478 and 350 bp for S.aureus and toxins (SEA, SEB and TSST-1) respectively.
To determine their suitability to PCR, four different template preparation methods viz. genomic DNA extraction, heat lysis, lysis buffers-1 and 2 were compared, of which heat lysis was found to be efficient and convenient. The specificity for S.aureus and toxins was tested using primers from nuc gene with three Staphylococcus spp and nine other non- S.aureus strains, which gave specific products at 279bp. The minimum detection level was 1cfu/ml for S.aureus.
Evaluation of two selective broths, i.e TSB and NB for PCR compatibility was done, which revealed that TSB was superior than NB. Spiking studies
were carried out by inoculating with pure culture of S.aureus in selective enrichments broths (18h and 24h), which revealed that 24 hours incubation was more effective.
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Keywords
bacteria, pcr, toxins, meat, sampling, antibiotics, livestock, biological phenomena, animal husbandry, genes