Bile Acid Oligomers and Their Combination with Antibiotics To Combat Bacterial Infections.

The ever-growing risk of bacterial resistance is a critical concern. Among the various antimicrobial resistant bacterial strains, methicillin and vancomycin resistant Staphylococcus aureus are among the most dreadful, causing serious complications. On the basis of the hypothesis that microbes have reduced ability to develop resistance against membrane targeting antibiotics, bile acid oligomers having unique facially amphiphilic topologies were designed and synthesized. The oligomers with specific linkers exhibited potent and selective antibacterial activity against Gram-positive bacteria. The lead compounds also improved the efficacy of a range of known antibiotics belonging to different classes when tested in combination. The active dimers were found to be effective against antibiotic-resistant clinical isolates of S. aureus, including multidrug resistant isolates. A significant inhibitory activity against S. aureus biofilm, a highly drug-resistant bacterial phenotype often unresponsive to antibiotic therapy, was also noticed. No adverse effects were observed by these dimers in a cell viability assay against HEK293 cells.