Evaluation of <i>Salmonella</i> isolates obtained from poultry farms in Abia and Imo States for the presence of plasmids

Abstract

This study was conducted to determine whether there exists the presence of plasmid from Salmonella isolated from poultry farms in Abia and Imo states southeast Nigeria. Forty Salmonella isolates were used for the study. The alkaline phosphate method of Birnboin and Doly was employed. Three buffers A, B and C made up of different concentrations and volumes with adjusted pH were used. A (400 mM Tris, 200 mM Na Ethylenediaminetetraacetic acid), B (3 M Na, acatic acid) and C (10 mM Tris, 2 M Na Ethylenediaminetetraacetic acid). The test organisms sub-cultured on MacConkey agar (MCA) were processed at various centrifugation rates and time. The suspected pure plasmid deoxyribonucleic acid was mixed with ethidium bromide and loading dye using agarose gel. The set up was viewed under ultraviolet transillumination with gel documentation apparatus. Plasmid cure was conducted with ten multidrug resistant Salmonella isolates. Danifor Biotechnology method was used for the plasmid curing experiment. Three curing agents, sodium deodecyl sulphate curing agents (100), sodium deodecyl sulphate (10 g or 10%) and nutrient broth (100 ml) were used. Plasmid DNA was detected from the Salmonella isolates evidenced with bands at 100 bp. There was plasmid cure as supported by the zones of inhibition by some of the antibiotics when compared with the original isolates.

Keywords: Cure, DNA, multidrug resistant isolates, plasmid, Salmonella