10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 1 2015 (January - March) Statins have been widely studied as antibacterial compounds, but the mechanism of their bacterial inhibition is still not known. In the present investigation two statins, atorvastatin and rosuvastatin, were tested for their antimicrobial activity against lessThan i greaterThan Pseudomonas aeruginosa lessThan /i greaterThan and both showed MIC of 625μg/ml. Both the statins shared structural similarity with quorum sensing signal molecule of Gram negative bacteria i.e. N-acylhomoserine lactone (AHL) but showed no functional agonist or antagonist activity, as indicated by QS-deficient lessThan i greaterThan Agrobacterium tumefaciens lessThan /i greaterThan A136 biosensor strain. Atorvastatin increased the flagella-mediated swarming, swimming and type IV pili-mediated twitching motilities and biofilm formation in lessThan i greaterThan P. aeruginosa lessThan /i greaterThan PAO1 while rosuvastatin decreased all three motilities slightly but had no effect on biofilm formation. SAJAL SARABHAI, LOVEDEEP KAUR DHALIWAL, NEENA CAPALASH AND PRINCE SHARMA Atorvastatin /Rosuvastatin/ Biofilm/ Motilities/ Pseudomonas aeruginosa/ Quorum sensing 01-08