Caracterización fenotípica y molecular de colífagos líticos

Abstract

Economic losses in the poultry sector are increasing due to avian colibacillosis and treatments for this disease are increasingly ineffective due to bacterial resistance to antimicrobials. The objective of this study is to characterize specific lytic bacteriophages for Escherichia coli (E. coli) as a biocontrol alternative for avian colibacillosis. This was carried out in the Azuay province, Ecuador and bacteriophages were obtained with which its specificity against E. coli, its lytic capacity, phenotype and genotype was determined, for this 36 environmental samples of poultry litters and production farms were collected, then They were transported to the Molecular Biology laboratory of the Faculty of Agricultural Sciences of the University of Cuenca. For isolation, the samples were clarified by centrifugation at 14,000 gravities for 10 min at 4 ° C. The supernatant was passed through a 0.22 µm membrane filter. Then with these we proceeded to the infection of non-pathogenic E. coli cultures, where we assessed the presence of phages. The isolation and characterization (RFLP) of the phage DNA was done with the methods described by Kutter and Sulakvelidze in 2005 and in Faiza et al. In 2002. 36 isolates of coliphages were obtained, which were evaluated against pathogenic strains of E. coli (10 strains), of these phages 25% (9 phages) had a null lytic capacity, 61.11% (22 phages) affected between 10-50% of the strains and 13.89% (5 phages) infected 60 and 70%. These latter phages with higher lytic capacity were genotypically characterized by RFLP, obtaining as a result 4 different coliphages. It is concluded that in environmental samples a variety of coliphages can be found capable of carrying out a biocontrol of E. coli, which can be used for prevention and treatment of avian colibacillosis.