Table 3.

Studies demonstrating QS disruption by signals degradation.

Models	Strains	Anti-QS agents	Target	Effects	Ref
In-vitro	Pseudomonas aeruginosa	Lactonase SsoPox	Degradation of the acyl-homoserine lactones	Inhibited the virulence of 51 clinical P. aeruginosa isolated from diabetic foot ulcers by decreasing the secretion of proteases and pyocyanin, and biofilm formation	[72]
In-vitro, rats	Pseudomonas aeruginosa PAO1	Lactonase SsoPox-1	Degradation of the acyl-homoserine lactones	Decreased lasB virulence gene activity, pyocyanin synthesis, proteolytic activity, and biofilm formation. Reduced the mortality of rats with acute pneumonia from 75% to 20%. Attenuated lung damage of the rat model	[73]
In-vitro	A.baumannii S1,S2,S3	Engineered lactonase	Degradation of the acyl-homoserine lactones	Reduced the biomass of A. baumannii associated biofilms	[74]
In-vitro	Pseudomonas aeruginosa	Lactonase Aii810	Degradation of the acyl-homoserine lactones	Attenuated Virulence Factors and Biofilm Formation. Degraded N-butyryl-L-homoserine lactone and N-(3-oxododecanoyl)-L-homoserine lactone, by 72.3 and 100%	[75]
In-vitro	Pseudomonas aeruginosa	Overexpression of lactonase enzyme AHL-1	Degradation of the acyl-homoserine lactones	Reduced the protease, pyocyanin, rhamnolipids. Inhibited the activities on the swarming motility and biofilm formation	[76]
In-vitro	Pseudomonas aeruginosa	Novel Lactonase cloned by bpiB01, bpiB04	Degradation of the N-(3-oxooctanoyl)-L-homoserine lactone	Inhibited motility and biofilm formation	[77]
In-vitro	Pseudomonas aeruginosa PAO1	Lactonase AiiK	Degradation of the acyl-homoserine lactones	Inhibited the biofilm formation and attenuates extracellular proteolytic activity and pyocyanin production	[78]
In-vitro	Pseudomonas aeruginosa PAO1	N-Acyl-Homoserine Lactone Acylase PA2385	Degradation of 3-oxo-C12-HSL and 2-heptyl-3-hydroxy-4(1H)- quinolone	Reduced production of the virulence factors elastase and pyocyanin	[85]
In-vitro, C. elegans	Pseudomonas aeruginosa PAO1	NADP-dependent short-chain dehydrogenase/reductase (bpiB09)	Inactivation of N-(3-oxo-dodecanoyl)-L-homoserine lactone (3-oxo-C12-HSL)	Reduced pyocyanin production, decreased motility, poor biofilm formation and absent paralysis of C. elegans	[91]
In-vitro, plant	Pseudomonas aeruginosa PAO1	3-hydroxy-2-methyl-4(1H)-quinolone	Catalyzing the conversion of PQS to N-octanoylanthranilic acid and carbon monoxide	Reduced expression of the PQS biosynthetic gene pqsA, expression of the PQS-regulated virulence determinants lectin A, pyocyanin, and rhamnolipids, and virulence in plant	[94]