Isolating and identifying cultivable antimicrobial producing agents bioprospects from hypersaline microbial mats and forests' soils in Puerto Rico

Today, the increase of antibiotic resistant microorganisms and the increase and prevalence of infections over other diseases is estimated between 45% and 87%. To counteract this issue, approaches such as understanding the antibiotic resistance phenomena, or searching for novel antimicrobial agents have been developed.  The main focus of this research is to find cultivable bioprospects from Microbial Mats (MM) and forests soil (FS) in Puerto Rico, capable of producing new antimicrobial agents. The microbial targets included Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus epidermidis. Samples of MM and FS were homogenized and serial dilutions were performed using 0.85% NaCl. The diluted samples were spreaded on Nutrient Agar and Tryptic Soy Agar. The samples were incubated at 25ºC and 37ºC, for 24 hrs and colonies showing an inhibition halos were isolated as putative antimicrobial agents producing bioprospects (PAAPB). The isolates were tested for inhibition activity against the targets, by Kirby Bauer, and radial inhibition tests. The bioprospects were identified microbiologically and molecularly by PCR.  A total of 35 PAAPB were isolated on this study. The preliminary testing of the candidates confirmed that two bioprospects inhibited K. pneumoniae, and S. epidermidis, one P. aeruginosa and five E. coli. The bacterial DNA was extracted effectively and its 16S rRNA amplified by PCR. In silico analysis are in progress to determine the identity of the isolates. After identifying the gene(s) responsible for the inhibition by Tn mutagenesis, combinatorial chemistry approaches will be performed to increase the inhibition potential.