Antibiotic Resistance in Staphylococcus aureus: Effects of Quorum Sensing Inhibition and DNA Fragmentation

Abstract

BackgroundAntimicrobial resistance (AMR) is a global crisis, causing 2.8 million infections and 35,000 deaths annually. Staphylococcus aureus is mainly responsible for causing these challenging infections through biofilm formation and the action of efflux pumps. A limited number of studies on Hop (Humulus lupulus) have shown its potential to inhibit quorum sensing in pathogenic bacteria. ObjectiveTherefore, a novel treatment approach was used in this study, which investigated Hops {beta}-acids, particularly the combination of colupulone and n+adlupulone, as well as in combination with fluoroquinolone antibiotics ciprofloxacin and ofloxacin. As ciprofloxacin remains a highly effective antibiotic against Staphylococcus aureus but resistance can develop, and ofloxacin exhibits naturally higher resistance in S. aureus, this study hypothesized that combining Hop (containing colupulone & n+adlupulone) with the two antibiotics separately would result in a greater reduction in biofilm growth of S. aureus compared to their individual potency levels. MethodsAntimicrobial activity was assessed using disk diffusion assays and minimum inhibitory concentration for biofilms at multiple concentrations through 2-fold serial dilutions. ResultsOur data demonstrate that Hop-derived {beta}-acids possess direct antimicrobial activity and when combined with the fluoroquinolone antibiotics, exhibit additive or synergistic effects by acting on different targets in Staphylococcus aureus. ConclusionsThis study provides insight into how natural products can potentially mitigate the development of resistance to antibiotics like ciprofloxacin in the highly pathogenic bacterium S. aureus. It also highlights how adding natural compounds could improve drug effectiveness. Therefore, this demonstrates the potential of natural compounds and antibiotics like ofloxacin, which are known to be ineffective against S. aureus. It offers a promising natural-conventional hybrid approach to addressing antimicrobial resistance.