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Published on: January 1, 2016
Discovery of quaternary ammonium compounds with broad antibacterial activity and efficacy in S. aureus infection
Akash Shinde1, Deepanshi Saxena2, Rahul Maitra2
1Department of Natural Products and Medicinal Chemistry, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, 500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, India.
Abstract:
Antimicrobial resistance (AMR) has become a significant global health concern, contributing heavily to the morbidity and mortality associated with both hospital-acquired (nosocomial) and community-acquired infections. In this context, we investigated the antibacterial potential of quinoline-based quaternary ammonium compounds (QACs) against Gram-positive bacteria, including multidrug-resistant (MDR) strains. Compound 20 was identified through a detail Structure-Activity-Relationship study and demonstrated strong antibacterial potential with an MIC of 0.125 μg/mL against S. aureus. This compound is effective against clinical MDR-MRSA and VRSA. Of note, 20 effectively inhibited bacterial growth in both planktonic and biofilm forms in a concentration-dependent manner. It's favorable toxicity profile (SI 72 w.r.t. CHO-K1 cells, HC50 of >100 μg/mL against human RBC) and prolonged post-antibiotic effect (PAE) compared to vancomycin highlights its potency as a safe therapeutic agent. Notably, the compound's in vitro efficacy was successfully translated in vivo, supporting its potential for development into a novel treatment for drug-resistant S. aureus infections, particularly for topical applications.
Insights
A novel quinoline-based quaternary ammonium compound (QAC) shows potent antibacterial activity against drug-resistant bacteria like MRSA and VRSA. This compound demonstrates efficacy in both lab and animal models, suggesting potential for new topical treatments.
Area of Science:
- Medicinal Chemistry
- Antimicrobial Resistance Research
- Drug Discovery
Background:
- Antimicrobial resistance (AMR) is a critical global health issue, increasing morbidity and mortality from infections.
- Gram-positive bacterial infections, including those caused by multidrug-resistant (MDR) strains, pose a significant challenge.
Purpose of the Study:
- To investigate the antibacterial potential of quinoline-based quaternary ammonium compounds (QACs).
- To identify and characterize novel QACs effective against Gram-positive and MDR bacteria.
Main Methods:
- Structure-Activity-Relationship (SAR) studies were conducted to identify potent compounds.
- Minimum Inhibitory Concentration (MIC) assays were performed against various bacterial strains.
- Cytotoxicity and post-antibiotic effect (PAE) were evaluated.
- In vitro and in vivo efficacy studies were carried out.
Main Results:
- Compound 20, a QAC, exhibited potent activity against Staphylococcus aureus with an MIC of 0.125 μg/mL.
- Compound 20 demonstrated efficacy against clinical multidrug-resistant Methicillin-resistant Staphylococcus aureus (MDR-MRSA) and Vancomycin-resistant Staphylococcus aureus (VRSA).
- The compound inhibited both planktonic and biofilm bacterial growth concentration-dependently, with a favorable toxicity profile and prolonged PAE compared to vancomycin.
Conclusions:
- Compound 20 shows significant promise as a therapeutic agent against drug-resistant Gram-positive bacterial infections.
- The compound's efficacy in vitro and in vivo supports its potential development for novel treatments, especially for topical applications.
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