Table 6.

Studies demonstrating the synergistic effects of anti-QS agents and antibiotics.

Models	Strains	Anti-QS agents	Target	Effects	Ref
Mice	Pseudomonas aeruginosa	Furanone C-30, ajoene or horseradish juice extract in Combination curcumin	QS inhibition enhance the sensitivity of pathogen to antibiotics	Resulted in an increased clearance of Pseudomonas aeruginosa in a foreign-body infection model.	[107]
In-vitro	Pseudomonas aeruginosa	with tobramycin, gentamicin and azithromycin	Induced concentrations of C12- homoserine lactone and C4- homoserine lactone	Curcumin showed synergistic effects with azithromycin and gentamicin. Combination use reduced QS-related virulence factors. Downregulated QS-related genes.	[112]
In-vitro	Staphylococci	Epigallocatechin-3-gallate with Tetracycline	Inhibition of the activity of Tet(K) pumps efflux pumps of a different class Tet(B)	Enhanced the bactericidal effect of Tetracycline on Staphylococci.	[113]
In-vitro	Pseudomonas aeruginosa	N-(2-pyrimidyl) butanamide, C11	Downregulation of rhl, rhlA and lasB genes	Increased the susceptibility to antibiotics and attenuated the pathogenicity of the bacterium.	[115]
In-vitro	Staphylococcus aureus (methicillin-resistant S. aureus)	Farnesol with β-lactam antibiotics	Inhibition of lipase activity and disruption of the cytoplasmic membrane through the leakage of potassium ions	Attenuated the rate of growth of bacteria, and countering ubiquitous β-lactam resistance in bacteria.	[116, 117]
In-vitro,   C. elegans, Galleria mellonella, mice	Burkholderia cenocepacia, Staphylococcus aureus,   Escherichia coli	Baicalin hydrate, cinnamaldehyde, hamamelitannin with Tobramycin, vancomycin, and clindamycin;	Inhibition of biofilm formation. QS inhibition enhance the sensitivity of pathogen to antibiotics	Combining the use of antibody and anti-QS agents increased susceptibility of the bacteria to the antibiotic, and increased host survival rate after infection	[118]