Antibacterial, Antibiofilm, and Anti-Quorum Sensing Potential of Novel Synthetic Compounds Against Pathogenic Bacteria Isolated From Chronic Sinusitis Patients

Abstract

Quorum sensing (QS) is a major controller of virulence and biofilm formation in pathogenic bacteria. The aim of the research was to screen novel synthetic compounds (18) from 2 series (Pyrazole and Diene dione) for quorum sensing and biofilm inhibitory potential against resistant pathogens isolated from patients with chronic sinusitis. Most of the compounds have documented zone of inhibition against Gram positive strains Staphylococcus aureus, Enterococcus faecalis and moderate activity against Gram negative Klebseilla pneumoniae and Proteus mirabilis in comparison with standard antibiotic. Compounds Q1 and Q7 have given the maximum zone of inhibition 18 and 20 mm with MICs 0.312 mg/mL and .156 mg/mL against S aureus and E faecalis, respectively. Some compounds were equally potent at inhibiting the formation of biofilm which later established by phase contrast microscopy. Regarding quorum sensing inhibition, the tested concentration of synthetic compound UA3 0.313 mg/mL inhibited violacein production without decreasing Chromobacterium pseudoviolaceum count which was significantly lower than determined MIC’s. It was depicted from the results that selected compounds exhibited low level of cytotoxicity toward human red blood cells. Hence, these findings revealed that most novel compounds were effective antibacterial, whereas compound UA3 has shared significant anti-quorum sensing potential against Chromobacterium pseudoviolaceum.

Evaluation of novel compounds as anti-bacterial or anti-virulence agents

“…In another study, novel synthetic compounds (18) from 2 series (Pyrazole and Diene dione) were screened for QS and biofilm inhibitory potential against resistant pathogens isolated from patients with chronic sinusitis (Rafiq et al, 2022). Findings within this study revealed that most novel compounds were effective anti-bacterial agents, some compounds were potent inhibitors of biofilm formation, whereas compound UA3 has shared significant anti-quorum sensing potential against Chromobacterium pseudoviolaceum (Rafiq et al, 2022). In the study performed by Bernabè et al (2022) in house library of phenolic derivatives (81 compounds) were tested for anti-QS activity.…”

Biology and Regulation of Staphylococcal Biofilm

“…Dozens of recent papers described different attempts to reduce biofilm formation or to destroy an already-formed biofilm in order to avoid the removal or replacement of an implanted material. Enzymes, antimicrobial peptides, bacteriophages, and natural compounds from vegetal origins have been used, mainly in vitro, with variable results [ 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 ]. Interesting observations were reported by Caballero Gomez in the field of meat-chain production using natural compounds extracted from essential oils alone or in combination with EDTA [ 133 ].…”

“…Other natural molecules have been identified from human milk, such as oligosaccharides, that allow for an appreciable decrease in S. aureus biofilm formation [ 136 ]. Other groups reported the efficacy of different synthetic molecules of an organic [ 134 , 139 ] or peptidic [ 135 ] nature on biofilm formation with clear success. Impressive results were obtained using a non-toxic acyclic amine derivative that yielded an extensive reduction of a biofilm and bacterial count in a model of urinary catheter infection [ 139 ].…”

Pharmacological Activities and In-Silico Studies of Bioactive Compounds Identified in Organic Fractions of the Methanolic Extract ofCitrullus Colocynthis

“…C. colocynthis fractions (ethyl acetate and chloroform) were assessed for minimum inhibitory effect against selected pathogens by microdilution method using resazurin-based assay. 29 In a microtitre plate, 100 μL of nutrient broth was added in each well. Following this, 100 μL of 250 mg/mL ethyl acetate fraction was added in each first well of row A-D and two-fold diluted till column 10.…”