How beta-lactam antibiotics enter bacteria: a dialogue with the porins

James, C; Mahendran, K; Molitor, A; Bolla, JM; Bessonov, A; Winterhalter, M; Pages, JM

Abstract

BACKGROUND:Multi-drug resistant (MDR) infections have become a major concern in hospitals worldwide. This study investigates membrane translocation, which is the first step required for drug action on internal bacterial targets. beta-lactams, a major antibiotic class, use porins to pass through the outer membrane barrier of Gram-negative bacteria. Clinical reports have linked the MDR phenotype to altered membrane permeability including porin modification and efflux pump expression.
METHODOLOGY/PRINCIPAL FINDINGS:
Here influx of beta-lactams through the major Enterobacter aerogenes porin Omp36 is characterized. Conductance measurements through a single Omp36 trimer reconstituted into a planar lipid bilayer allowed us to count the passage of single beta-lactam molecules. Statistical analysis of each transport event yielded the kinetic parameters of antibiotic travel through Omp36 and distinguishable translocation properties of beta-lactams were quantified for ertapenem and cefepime. Expression of Omp36 in an otherwise porin-null bacterial strain is shown to confer increases in the killing rate of these antibiotics and in the corresponding bacterial susceptibility.
CONCLUSIONS/SIGNIFICANCE:
We propose the idea of a molecular "passport" that allows rapid transport of substrates through porins. Deciphering antibiotic translocation provides new insights for the design of novel drugs that may be highly effective at passing through the porin constriction zone. Such data may hold the key for the next generation of antibiotics capable of rapid intracellular accumulation to circumvent the further development MDR infections.

Citation

James, C., Mahendran, K., Molitor, A., Bolla, J., Bessonov, A., Winterhalter, M., & Pages, J. (2009). How beta-lactam antibiotics enter bacteria: a dialogue with the porins. PLoS ONE, 4(5), e5453. https://doi.org/10.1371/journal.pone.0005453

• Journal Article Type: Article
• Publication Date: May 12, 2009
• Deposit Date: Jan 26, 2015
• Publicly Available Date: Apr 5, 2016
• Journal: PLoS One
• Publisher: Public Library of Science
• Peer Reviewed: Peer Reviewed
• Volume: 4
• Issue: 5
• Pages: e5453
• DOI: https://doi.org/10.1371/journal.pone.0005453
• Publisher URL: http://dx.doi.org/10.1371/journal.pone.0005453
• Related Public URLs: http://www.plosone.org/
• Additional Information: Funders : Marie Curie Research Training Networks;COST Action;Universite de la Mediterranee and Service de Santé des Armees;Marseille Allocation Accueil; Grant Number: EU-grant MRTN-CT-2005-019335 (Translocation); Grant Number: COST Action BM0701 “ATENS”; Grant Number: the Universite de la Mediterranee and Service de Santé des Armees (livre rouge operation23e)