EVALUATION OF ANTIMICROBIAL ACTIVITY OF HYBRID BATERIOCINS IN PATHOGENIC STRAINS

NAVARRO S; CHALÓN MC; BARRIONUEVO, E; MERLETTI G; ASSA,J; BELLOMIO A

Parana, Entre Rios

Congreso; 54 Reunion anual de la Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular; 2018

Sociedad Argentina de Investigacion en Bioquimica y Biologia Molecular

Bacteriocins are bacterial antimicrobial peptides. Enterocin CRL35 and microcin V are produced by Enterococcus mundtii and Escherichia coli, respectively. They are active on microorganisms phylogenetically related to the producer strain. Ent35-GGG-MccV is a hybrid bacteriocin obtained by fusion of the genes of Enterocin CRL35 and Microcin V with a sequence encoding for a hinge region of three glycine between them. New peptides derived from Ent35-GGG-MccV with improved bioactivity were obtained by saturation mutagenesis focused on the hinge region.The aim of this work is to compare the antimicrobial potency and the spectrum of action of the different variants against indicator and pathogenic strains related to food-borne diseases. To compare the activity of the different variants, determinations were made of the minimum inhibitoryconcentration and a count of viable cells of bacterial suspensions treated with the peptides. Moreover, the bacteriocins were tested against Shigella spp. isolates from fecal sample in child with GI disease. As a conclusion, all the hybrid peptides were able to decrease the viability of the indicator strains and two variants (Ent35-GYG-MccV and Ent35-GNG-MccV) showed higher antimicrobial activity than the original bacteriocin, on E. coli and Listeria monocytogenes. In addition, the peptides exhibited antimicrobial activity against all the strains of Shigella sonnei tested. The approach was highly successful to obtain mutants with improved bioactivity with respect to the original hybrid.