Bacterial resistance to antibiotics has emerged as a considerable threat to human health. Methicillin-resistant Staphloccous aureus (MRSA) and vancomycin-resistant enterococci (VRE) are multi-drug resistant bacteria that cause life threatening infections in the hospital setting and in some cases have leapt to the larger community. It is clear that new strategies and tactics are needed to combat these insidious bacteria. Often times, bacteria owe their antibiotic resistance to the proteins encoded by plasmids that they harbor. Plasmids are small, circular, extra-chromosomal pieces of DNA that can be transferred from one bacterium to another. These plasmids often contain genes that encode proteins that confer resistance to a wide array of antibiotics. Indeed, for several classes of antibiotics (including beta-lactams, macrolides, and aminoglycosides) plasmid-borne resistance is ubiquitous. In addition, many of the worst multi-drug resistant bacteria (including MRSA and VRE) are resistant by virtue of the plasmid they harbor. Proposed herein is a strategy to attack this plasmid-encoded resistance through the creation of """"""""anti-plasmid"""""""" agents, small molecules that will vanquish the plasmid from the cell, thus rendering the bacteria sensitive to antibiotics. These compounds are designed to mimic a known, naturally occurring mechanism for plasmid elimination, known as plasmid incompatibility. The bio-molecules that determine plasmid incompatibility are typically small pieces of RNA and DNA iterons. It has been shown that genetic mutation of these RNA incompatibility determinants disrupts RNA loop-loop interactions and leads to plasmid elimination.
In Specific Aims 1 and2 of this proposal, small molecules are described that will disrupt the RNA loop-loop interaction in a completely analogous manner, thus leading to plasmid elimination.
Specific Aims 3 and 4 describe studies on the mechanism and inhibition of the plasmid replication initiation protein, RepA. The successful completion of the experiments described herein could lead to a dramatic change in the manner in which antibiotic resistant infections are treated.
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