Colostrum Hexasaccharide, a Novel Staphylococcus aureus Quorum-Sensing Inhibitor

Abstract

The discovery of quorum-sensing (QS) systems regulating antibiotic resistance and virulence factors (VFs) has afforded a novel opportunity to prevent bacterial pathogenicity. Dietary molecules have been demonstrated to attenuate QS circuits of bacteria. But, to our knowledge, no study exploring the potential of colostrum hexasaccharide (CHS) in regulating QS systems has been published. In this study, we analyzed CHS for inhibiting QS signaling in Staphylococcus aureus. We isolated and characterized CHS from mare colostrum by high-performance thin-layer chromatography (HPTLC), reverse-phase high-performance liquid chromatography evaporative light-scattering detection (RP-HPLC-ELSD), 1 H and 13 C nuclear magnetic resonance (NMR), and electrospray ionization mass spectrometry (ESI-MS). Antibiofilm activity of CHS against S. aureus and its possible interference with bacterial QS systems were determined. The inhibition and eradication potentials of the biofilms were studied by microscopic analyses and quantified by 96-well-microtiter-plate assays. Also, the ability of CHS to interfere in bacterial QS by degrading acyl-homoserine lactones (AHLs), one of the most studied signal molecules for Gram-negative bacteria, was evaluated. The results revealed that CHS exhibited promising inhibitory activities against QS-regulated secretion of VFs, including spreading ability, hemolysis, protease, and lipase activities, when applied at a rate of 5 mg/ml. The results of biofilm experiments indicated that CHS is a strong inhibitor of biofilm formation and also has the ability to eradicate it. The potential of CHS to interfere with bacterial QS systems was also examined by degradation of AHLs. Furthermore, it was documented that CHS decreased antibiotic resistance in S. aureus. The results thus give a lead that mare colostrum can be a promising source for isolating a next-generation antibacterial.

Resilience of bacterial quorum sensing against fluid flow

“…aeruginosa QS systems support the idea that fluid flow is an important element of a biofilm’s physical environment that can co-regulate the onset of QS as it decreases the local QS inducer concentration by convection. In particular, these results cast doubt on any direct application where results about the effectiveness of QS antagonists or biocides obtained under quiescent conditions 43 44 45 46 are translated to habitats exposed to fluid flow. Instead, we suggest that screening assays for new approaches to interfere with QS should explicitly include fluid flow as a fundamental test parameter.…”

Impact of phenolic compounds in the acyl homoserine lactone-mediated quorum sensing regulatory pathways

“…Standard disk–diffusion assay was used to detect anti-QS activity of the 5 phenolic compounds utilizing biomonitor strain, C.violaceum (ATCC12472) by slightly modifying a previously reported method 84 . C. violaceum ATCC12472 was poured on molten LB agar medium in plastic petri dish (90 × 15 mm) to make 5 × 10 6 CFU/mL.…”

Scaffold of Selenium Nanovectors and Honey Phytochemicals for Inhibition of Pseudomonas aeruginosa Quorum Sensing and Biofilm Formation

“…Emergence of multi-drug resistant bacteria has driven studies for disabling virulence preferentially through quorum sensing (QS) inhibition tactics instead of bactericidal and bacteriostatic strategies (Singh et al, 2009a; Defoirdt et al, 2013; Kim et al, 2015; Lidor et al, 2015; Srivastava et al, 2015; Wang et al, 2015; Yang et al, 2015). P. aeruginosa , a Gram-negative bacterium causes cystic fibrosis in immunocompromised patients, burn units of hospitals, and in implanted medical devices including intubation tubes and stents (Singh et al, 2012; Singh B. R. et al, 2015; Kalferstova et al, 2016).…”