Antibacterial Small Molecules That Potently Inhibit Staphylococcus aureus Lipoteichoic Acid Biosynthesis

The rise of antibiotic resistance, especially in Staphylococcus aureus, and the increasing death rate due to multiresistant bacteria have been well documented. The need for new chemical entities and/or the identification of novel targets for antibacterial drug development is high. Lipoteichoic acid (LTA), a membrane-attached anionic polymer, is important for the growth and virulence of many Gram-positive bacteria, and interest has been high in the discovery of LTA biosynthesis inhibitors. Thus far, only a handful of LTA biosynthesis inhibitors have been described with moderate (MIC=5.34 μg mL^-1 ) to low (MIC=1024 μg mL^-1 ) activities against S. aureus. Herein we describe the identification of novel compounds that potently inhibit LTA biosynthesis in S. aureus, displaying impressive antibacterial activities (MIC as low as 0.25 μg mL^-1 ) against methicillin-resistant S. aureus (MRSA). Under similar in vitro assay conditions, these compounds are 4-fold more potent than vancomycin and 8-fold more potent than linezolid against MRSA.