INVESTIGADORES
DELGADO Monica Alejandra
congresos y reuniones científicas
Título:
Characterization of new antimicrobials produced by clinical isolates from fecal samples for biotechnological application
Autor/es:
RENTERIA J,; APAZA N; DELGADO M. A; PESCARETTI, MM,
Lugar:
Salta
Reunión:
Congreso; 54ta Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB).; 2019
Institución organizadora:
SAIB
Resumen:
CHARACTERIZATION OF NEW ANTIMICROBIALS PRODUCED BY CLINICAL ISOLATES FROM FECAL SAMPLES FOR BIOTECHNOLOGICAL APPLICATIONRenteria J, Apaza N, Delgado MA, Pescaretti MM.INSIBIO (CONICET-UNT) and Instituto de Química Biológica ?Dr. Bernabé Bloj?. E-mail: mail:justi.renteria@gmail.comFoodborne diseases are one of the most widespread problems of the worldwide population and are produced by the ingestion of contaminated water or food. We analyzed the Shigella clinical isolates (CI), from patients suffered gastrointestinal infections during the summer period 2013-2017 from Catamarca, Santiago del Estero and Tucumán patients (Northwest Argentina region), in order to select those capable to produce antimicrobial compounds, using the plate?s diffusion technique. We found that 11 of the total analyzed samples (371 CI) were able to produce an antimicrobial agent that inhibited the growth of the Escherichia coli AB1133 used as an indicator sensitive strain. In addition, in this work we characterized these compounds studying its thermotolerance (100°C), stability to pH (5 and 8) and proteinase treatments, as well its cross immunity against other bacteriocin producer strains, and its spectrum of antimicrobial action, between other characteristics. To complete the proprieties and classification of these compounds, the molecular weight was also estimated by the ability of such agents to diffuse through dialysis membranes with different cut-off size pores, mainly in the range of 10 to 12000 Da. The results indicate that the total numbers of antimicrobials are tolerant to the temperature (100°C) and sensitive to the proteinase K treatment, which are two desirable characteristics for use as food preservatives. In addition, we found that only 2 compounds are affected by pH 8 treatment. The cross-immunity test showed that at least 3 antimicrobials have a different nature and can be classified as different agents. From this study, we select producer strains of these 3 new compounds and analyzed the bacterial growth and the antimicrobial production curve through the time. On the other hand, we investigated if the production of these antimicrobial agents was induced by mitomycin C (0,5 μg/mL), an inducer agent of the SOS system required to activates the synthesis of high molecular weight bacteriocins called colicins. In this work we demonstrated that 3 of the 11 antimicrobials studied presented important characteristics that enable their use and development as new antibiotics or new food preservatives and that at least one of them is a different compound to the typical colicins produced by Shigella.