Institution: Interamerican University Bayamón Campus

Email: dsanabria@intermetro.edu

Serious attention is needed because Methicillin-resistant Staphylococcus aureus (MRSA) continues gaining resistance to current antibiotics, and this scenario becomes complicated by the lack of a big pharma pipeline to develop new compounds that target superbugs. Although a limited number of compounds have been developed to address the MRSA resistance problem, discovering novel compounds with improved antibacterial activity is critically needed. Rationale: Synthetic unsaturated fatty acids (uFAs) are attractive candidates to become next-generation antibacterial agents for treating MRSA infections. In addition, synthetic uFAs hold promise because they appear to have multiple mechanisms of action, making it more difficult for bacteria to develop resistance to these drugs. Synthetic uFAs can directly kill multi-drug resistant bacteria at very low concentrations (i.e., micromolar and nanomolar levels). Recent experimental data suggest that the cytotoxic activity of either 2-hexadecynoic acid (2-HDA, triplebonded FA) or DAT-51(double-bonded FA) against MRSA is due to their ability to disrupt the cell membrane, possibly by pore formation. Therefore, further research is needed to elucidate the mechanism of action responsible for the antibacterial activity of synthetic uFAs, which represent a gap in knowledge. The longterm goal of this project is to define each of the mechanisms that explain the total antibacterial activity of uFAs and apply this knowledge to develop a next-generation of synthetic uFAs with even better efficacy as antibacterial agents. Our central hypothesis is that uFAs such as 2-HDA or DAT-51 can induce membrane disruption through direct pore formation. To test our central hypothesis, two independent but related Specific Aims are delineated. In the first aim, we will determine if the cytotoxic effect of either 2-HDA or DAT-51 on the growth of S. aureus requires incorporation into the bacterial membrane during different growth phases. The second aim was delineated to determine the inhibitory effect of 2-HDA or DAT-51 on the S. aureus peptidoglycan (PG) biosynthesis through the accumulation of Lipid II. The knowledge acquired from this project will have a high impact on the field because it will allow us to accomplish our objective in establishing the chemical and biological foundations required for the targeted design of the next generation of synthetic uFAs with improved antibacterial activity. Therefore, the successful completion of this project is likely to lead to the development of new therapeutic options to treat devastating MRSA infections.