Search of antimicrobial producer strains in clinical isolates from patients suffered gastrointestinal infections

MÓNICA A. DELGADO; MARÍA DE LAS MERCEDES PESCARETTI; JUSTINA RENTERIA

Tafi del Valle, Tucuman

Congreso; XXXV Jornadas Científicas Asociacion de Biologia de Tucuman; 2018

The goal of the present work was search antimicrobial producers strains in clinical isolates (CI) from patients suffered gastrointestinal infections. The strains analyzed in this study were isolated in the summer period 2013-2018 from patients with acute diarrhea in the Northwest Argentina region. The samples obtained were collected from three Hospitals of the five provinces that compose this region, Catamarca, Santiago del Estero and Tucumán. Here, we analyze the ability of these CI to produce growth inhibitory compounds using the plate?s diffusion technique and the E. coli AB1133 as an indicator sensitive strain. The results obtained demonstrated that the Shigella genus was the most common pathogen isolated in all provinces of our region, followed by Salmonella. According to different phenotypes of these CI, we conserved a total of 650 strains for next studies. We found here that 60 of 500 CI analyzed were able to produce an antimicrobial agent that inhibits the growth of the E. coli AB1133 sensitive strain. These antimicrobial compounds were classified according to thermotolerance, molecular weight, cross immunity, spectrum of antimicrobial action, between others. On these bases, we select and characterized the antimicrobial substances by a cell free supernatant obtained after the culture of the producer strains in LB during stationary phase, allowing us to identified different bacteriocin groups.