Table 1.

List of strains used.

strain	description	purpose	source or reference
Pseudomonas aeruginosa PAO1	wild-type prototroph	positive control for QSI	[12]
Chromobacterium violaceum ATCC 12472	type strain	QSI indicator strain	[22]
Rhizobium sp. NAO1	potential QSI screened in this study	effect on biofilm and virulence factors	[23]
environmental bacterial isolates	The 26th Ocean Survey	QSI screening	this work