Antibiotic resistance has caused current antibiotics to become ineffective in the clinical settings. With a shrinking pipeline of antibiotics, development of new antibiotics is essential for combating drug resistant versions of common bacterial infections as well as serious infections such as tuberculosis and typhoid fever. Especially for β-lactam antibiotics, resistance from acquired β-lactamases has caused the need for β-lactamase inhibitors to maintain efficacy. However, resistance has also developed to the β-lactam/β-lactamase inhibitor combinations due to extended spectrum β-lactamases such as carbapenemases and New Delhi metallo-β-lactamase 1 providing another avenue for widespread antibiotic resistance. Here, we develop novel antisense RNA based inhibitors to re-sensitize β-lactam resistant bacteria to a commonly used β-lactam antibiotic. We show that antisense molecules designed to target functional sites of β-lactamase (<i>bla</i>) transcript, are capable of re-sensitizing drug resistant <i>Escherichia coli</i> to β-lactam antibiotics following a translation inhibition mechanism. When screening independent cultures at the minimum inhibitory concentration for mutants that are capable of showing resistance to RNA inhibitor/β-lactam combination, only 2 out of 35 cultures showed emergence of adapted mutants with resistance to the therapeutic combination. Mutants that developed tolerance to the RNA inhibitor/β-lactam combination exhibited variable expression of representative stress response genes corresponding to the multiple antibiotic resistance (mar) regulon, general stress response, and SOS response; implying role of gene expression heterogeneity in development of resistance. Understanding how to design new antibiotics and the cellular response in developing tolerance to those antibiotics is important to start mitigating the antibiotic crisis.

Sequence-specific synthetic RNA silencing overcomes antibiotic resistance

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.