CIVETAN   23983
CENTRO DE INVESTIGACION VETERINARIA DE TANDIL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Inhibition of clinical isolates of VTEC by colicinogenic strains of Escherichia coli
Autor/es:
ETCHEVERRÍA ANALÍA; RUIZ, JULIA; GARCÍA MD; PADOLA NORA LÍA
Lugar:
Florencia
Reunión:
Simposio; 10th International Symposium on Shiga Toxin Producing Escherichia coli.; 2018
Institución organizadora:
Stefano Morabito Chair of the Local Organising Committee
Resumen:
Inhibition of clinical isolates of VTEC by colicinogenic strains of Escherichia coli García MD.1, Padola N., 1Ruiz MJ.1Etcheverría A.11Laboratorio de Inmunoquímica y Biotecnología, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, CICPBA, Facultad de Ciencias Veterinarias, UNCPBA, Tandil, Argentina.IntroductionVerotoxigenic Escherichia coli (VTEC), in particular serotype O157:H7, is responsible for producing diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS), Argentina has the highest global incidence of the latter. Currently, new tools for control and prevention of strains associated with HUS are being sought. It has been observed that strains of E.coli are capable of inhibiting the growth of pathogenic strains (including serotype O157:H7) by producing antibacterial peptides called bacteriocins, which are active against strains of the same or related species. In E. coli, they are classified by high and low molecular weight and called colicins and microcins respectivily. These strains are potential probiotics and sources of new purifiable antimicrobial compounds for use against pathogens.The aim of the present work is to evaluate the inhibitory activity of colicinogenic strains of E. coli isolated from bovine colon, against strains from clinical isolates of HUS.MethodsThe work was carried out with 6 colicinogenic E.coli strains isolated from bovine colon and 60 VTEC strains isolated from patients with diarrhea, hemorrhagic colitis and hemolytic uremic syndrome (HUS),of serotypes O157:H7 and non-O157. All these strains were supplied by the National Institute of Epidemiology (INE).The colicinogenic strains were puncture seeded and incubated ON at 37 ° C on LB broth, the colonies obtained were exposed to chloroform vapors for 1 hour and then left to dry for 30 minutes. When this was done, a soft agar containing 106 CFU/ml of each VTEC strain was poured on them. The same procedure was carried out to rule out a possible inhibitory effect of the pathogenic strains. The inhibitory activity was confirmed by presence of a translucent zone with absence of VTEC growth around the colony.Colicin and microcin genes were identified by Polymerase Chain Reaction (PCR) with known and high frequency bacteriocin primers coding for colicin Ia, S4, E1, E7, K and microcins B, V, B17, M, H47, C7 and J25. ResultsFrom 60 VTEC strains, 59 were inhibited by at least one colicinogenic strain. These strains, harboured colicin Ia (3 strains), E7, (2 strains), and of microcins: B (4 strains), M, J25, H47 (2 strains) and C7 (3 strains) confirmed by PCR.ConclussionThe results obtained contribute in the search for new antibacterial compounds that allow to face the present limitations for the use of antibiotics in the food industry, as well as in public health, mainly due to the appearance of resistant strains. The use of probiotic bacteria or their metabolites is a viable option to respond to this problem.