ISOLATION OF NATURAL PRODUCTS WITH ANTIMICROBIAL ACTIVITY FROM Streptomyces spp

VILLAFAÑE DL ; GRAMAJO H; ORTEGA FA,; CHIESA MA,; TESTERO SA; RODRÍGUEZ E

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Congreso; SAIB 2021; 2021

ISOLATION OF NATURAL PRODUCTS WITH ANTIMICROBIAL ACTIVITY FROM Streptomyces spp.*Ortega FA, Villafañe DL, Testero SA, Chiesa MA, Gramajo H, Rodríguez E.Instituto de Biología Molecular y Celular de Rosario (IBR ? CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Argentina. *E-mail: facu.a.ortega@gmail.comThe intense use of all classes of antibiotics has led to the emergence of resistant pathogenic bacteria or multiple drugs resistant bacteria (MDR). The increasing prevalence of MDR pathogens and the quick development of cross-resistance to new antibiotics, both in community and hospital infections, are limiting the treatment of bacterial infections representing one of the main causes of worldwide death. The lack of new antibiotics with new mechanisms of action, are nowadays one of the greatest challenges for the treatment of infectious diseases. One of the major current concerns is the emergence of MDR pathogens of the so-called ESKAPE pathogens (E. faecium, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa y Enterobacter spp.), and the lack of new antimicrobial compounds in development to fight these infections. Based on that, our group is interested in identifying new antimicrobial compounds from soil bacteria, including also antifungal compounds that could be used on agronomic plants as protecting agents against phytopathogenic fungi. The Streptomyces genus are well known to produce a wide range of natural compounds, including more than half of the natural products used in medicine. Thus, the aim of this work is to identify and characterize different antimicrobial compounds that are produced by Streptomyces strains isolated from soybean plants [Glycine max (L.) Merr]. So, from a strain collection isolated from rhizosphere of soybean plants, including endophytic bacteria, a strain called N14 was found to produce a compound active against MDR staphylococci (methicillin-resistant, macrolide-resistant, vancomycin resistant) by antibiogram assays. On the other hand, two strains (N2A and N9) showed antifungal activity against Diaporthe aspalathi and Macrophomina phaseolina, two important phytopathogenic fungi that bring serious problem on soybean. Subsequently, organic solvent extractions of the culture supernatant allowed us to purify each individual compound through chromatography and bioguided assays. These studies are promising based on that N14 strain is active against several MDR staphylococci and other Gram-positive bacteria including Mycobacterium sp. On the other hand, N2A and N9 produced antifungal compounds that are inactive against Saccharomyces cerevisiae, which make these compounds quite unique. Based on these results, it is possible to continue with the characterization of N14, N2A and N9 strains by means of genomic determination and bioinformatic methods. Isolation and purification of these antimicrobial compounds will be presented and discussed. The final goal will be the determination of the three-dimensional structure of these compounds through NMR assays.