Mitigation of acyl-homoserine lactone (AHL) based bacterial quorum sensing, virulence functions, and biofilm formation by yttrium oxide core/shell nanospheres: Novel approach to combat drug resistance

Abstract

The present study evaluated the efficacy of Y2O3:Tb (core) and Y2O3:Tb@SiO2 nanospheres (core/shell NSs) against virulence functions regulated by quorum sensing (QS) and biofilm formation in pathogenic bacteria. Scanning electron microscope (SEM) images were used to study the size, shape, and morphology. The images clearly displayed spherical shaped, mono-dispersed particles with narrow size distribution and an average grain size of 110–130 nm. The chemical composition of the samples was determined by using energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). We determined the impact of core and core/shell NSs on QS using sensor strains of Chromobacterium violaceum CVO26 and Pseudomonas aeruginosa PAO1 in a comparative study. Sub-MICs of core and core/shell NSs substantially suppressed QS-controlled violacein production in C. violaceum. Similar concentration-dependent effect of sub-MICs of synthesized core and core/shell NSs was observed in the QS-regulated virulence functions (elastase, total protease, pyocyanin production, swarming motility, and exopolysaccharide production) in PAO1. A concentration-dependent decrease (14–60%) was recorded in the biofilm forming capability of PAO1, upon treatment with core and core/shell NSs. Moreover, core/shell NSs were more effective in inhibiting biofilm at higher tested concentrations as compared to core-NSs. The synthesized NSs demonstrated significantly impaired attachment of cells to the microtiter plate indicating that NSs target biofilm inhibition at the attachment stage. Based on these results, we predict that core and core/shell NSs may be an alternative to combat the threat of drug-resistant pathogenic bacteria.

Microwave-Assisted Rapid Green Synthesis of Gold Nanoparticles Using Seed Extract of Trachyspermum ammi: ROS Mediated Biofilm Inhibition and Anticancer Activity

“…Listeria monocytogenes ATCC 19,114 and Serratia marcescens ATCC 13,880 were used in the present investigation to assess the antibacterial and antibiofilm activity of the synthesized AuNPs. Antibacterial potential of AuNPs was assessed in terms of MIC using the standard microbroth dilution method described previously [ 29 ].…”

Mechanism of Eucalyptus Volatile Oil Application for Preventing and Treating Pseudomonas Aeruginosa Infection in Vitro

“…Furthermore, SEM results revealed that bacterial bio lm formation can be delayed after exposing the PA to the eucalyptus volatile oil. Bio lm formation is closely related to bacterial resistance (17)(18)(19)(20). Hence, destroying drug resistance is one of the mechanisms of the eucalyptus volatile oil that can be used in clinical bacterial treatment.…”

Non-antibiotic methods against Pseudomonas aeruginosa include QS inhibitors: a narrative review

“…The environment makes PA more pathogenic, and this process is mainly controlled by these 4 systems (14,21). The characteristics of many PA virulence factors and distinct genes is principally regulated by 2 acyl-homoserine lactone (AHL) QS systems, LasI/LasR and RhlI/RhlR (8,20). LasR is central to the QS system (22).…”

“…The structure-activity relationship controlling LasR antagonism by V-06-018 has been reported. V-06-018 is a comparatively effective LasR antagonist in both Escherichia coli and PA LasR reporter strains and has been confirmed to inhibit virulence-related genes and phenotypes in PA (8). At the same time, V-06-018 lacks lactone parts so it is not easily hydrolyzed or enzymatically decomposed by AHL lactonases.…”

“…At the same time, V-06-018 lacks lactone parts so it is not easily hydrolyzed or enzymatically decomposed by AHL lactonases. Biochemical experiments have investigated the antagonistic mechanism of V-06-018 and its analogs, the compound is the most effective antagonist of LasR known and is a powerful probe to characterize the mechanism of action of LuxR-type QS and can be used in general chemical and biological studies in the growing field of QS (8).…”