Genetic spread of resistance and research of the virulence factors in Escherichia coli isolated from cohabitant animals in dairy farms

Abstract

In Brazil, the dairy cattle are present in 25% of bovine farms. The therapeutic use of antimicrobials, prophylactic or as growth promoter, has contributed for selection of resistance in commensal and pathogenic microorganisms. The spread of resistance and virulence genes is related to horizontal transfer mechanisms among microbial species and serving the food chain. Escherichia coli has commensal and pathogenic agents, and the ratio of these bacteria with the host allows the classification of these strains as reservoirs of resistance. Given the possibility of transference of genes between commensal and pathogenic strains within the host, this study proposes the isolation, identification and phenotypic and genotypic characterization of resistant E. coli in domestic animals (cows, calves, dogs, etc) and muscoid dipterous, cohabitant in farms; detection of virulence factors associated with bovine and human colibacillosis; investigation of the presence and classification of plasmids and integrons in resistant strains; ability to evaluate the spread of resistance genes by conjugation assays; determination of phylogenetic groups of resistant strains and evaluation of clonal profile resistant strains by PFGE. (AU)