Date of Completion

Spring 5-6-2012

Thesis Advisor(s)

Kumar Venkitanarayanan

Honors Major

Animal Science


Animal Sciences | Other Life Sciences


The emergence of multiple drug resistant (MDR) Acinetobacter baumannii has lead to an increased interest in finding alternative antimicrobial compounds for controlling the pathogen. The present study investigated the effect of three plant-derived antimicrobials, namely eugenol (EUG), carvacrol (CAR), and thymol (THY), on A. baumannii biofilms. Using concentrations equal to or greater than the minimum bactericidal concentration (MBC) of each compound, the ability of EUG, CAR, and THY to inactivate the mature biofilms of three strains of MDR A. baumannii on polystyrene microtiter plates and stainless steel coupons was examined. All three plant-derived compounds significantly inactivated the bioflims of all three A. baumannii strains tested (P < 0.05). After 10 min of incubation on polystyrene microtiter plates at 23°C, all three compounds eliminated all viable biofilm-associated A. baumannii cells, reducing the biofilm-associated bacterial population by >7.0 log CFU/ml. Eugenol and CAR exerted a similar effect at 37°C, while THY reduced the viable biofilm-associated bacterial population to 0.45 log CFU/ml. On stainless steel coupons incubated at 23°C, all three compounds reduced the viable biofilm-associated bacterial population by 6.5 log CFU/ml. Results indicate that EUG, CAR, and THY could potentially be utilized to control biofilms of A. baumannii on abiotic surfaces, thus preventing its persistence in the hospital environment. However, detailed follow up studies are needed.