Advanced Research Journal of Microbiology ISSN 1718-3499 Vol. 3 (1), pp. 078-082, April, 2016. © Advanced Scholars Journals
Full length Research paper
Transfer of Resistance Plasmids Between Escherichia coli Isolates from Domestic livestock
Nsofor CA* and NCD Ukwandu
1&2Department of Biotechnology, Federal University of Technology Owerri, Nigeria.
Corresponding Author: Email: [email protected]
Accepted 05 March, 2016.
Abstract
Drug-resistant commensal Escherichia coli isolates constitute a significant reservoir of antibiotic resistance determinants that can be transferred to those bacteria pathogenic for animals and/or humans. Bacterial conjugation is believed to play a major role in the dissemination of antibiotic resistance genes and virulence plasmids. In this study, we used conjugation assay to investigate the mobility of resistance plasmids between drug resistant Escherichia coli isolated from domestic animals and plasmid-free laboratory strain (gene-hog DH10B) as a recipient. Plasmid DNA was extracted using the alkaline SDS method and separated by agarose gel electrophoresis. Antibiotic susceptibility testing and plasmid profiling were used to confirm the transfer of resistance plasmid in the transconjugants. The result showed that the isolates harbored plasmids of different sizes in the range of 1 to 120KB. The rate of transferability of the plasmids among the isolates from different sample sources varied; highest conjugation efficiency was observed in isolates from goat ranging from 1.0 x 10-6- 9.4 x 10-7. The isolates from other sources viz: cattle, poultry and pig had conjugation efficiencies in the range of 1.2 x 10-6- 8.7 x 10-7,, 1.0 x 10-6- 9.4 x 10-7 and 1.4 x 10-7- 3.0 x 10-6 respectively. The results of this study suggest that conjugation could be an important mechanism for horizontal gene transfer between commensal and pathogenic bacteria. A better understanding of the mechanism and magnitude of resistance gene transfer may provide a strategy to reduce the potential for dissemination of these genes.
Keywords: Plasmid Transfer, Conjugation Efficiency, Antibiotic Resistance, Escherichia coli, Bacteria Pathogenic.