Effect of Cymbopogon citratus on biofilm production by multidrug resistant Acinetobacter baumannii

Abstract

Introduction and Aim: Acinetobacter baumannii, is the cause of many nosocomial infections which poses a serious threat to patients. Being a highly resistant organism, it has been placed in the critical priority list by WHO in 2017, thereby requiring newer effective drugs and alternative strategies. Increased antibiotic resistance has made it difficult to treat patients infected with this organism. The study aimed to find the biofilm forming ability of multidrug resistant A.baumannii causing respiratory tract infections, to find the genes responsible for biofilm production and to find the effect of Cymbopogon citratus (lemon grass) extract on biofilm. Materials and Methods: The antibiogram profile was studied for the Acinetobacter isolates obtained from endotracheal aspirates, endotracheal tubing tips by antibiotic susceptibility testing and Vitek-2. Genes known to be associated with biofilm production, (AbOmpA, Bap) in Acinetobacter were detected by Polymerase chain reaction (PCR). The Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Minimum Biofilm Inhibitory Concentration (MBIC), Minimum Biofilm Eradication Concentration (MBEC) of Cymbopogon citratus essential oil was determined by microtiter plate method. Results: Isolates that were tested were found to be Multidrug resistant (MDR) and Extremely drug resistant (XDR) with highest resistance to Carbapenems (95.83%). Activity of Cymbopogon citratus EO was determined. The isolates predominantly showed MIC of 2% and MBC was 8%. MBIC was found to be 1%. However, Cymbopogon citratus EO did not eradicate the preformed biofilms. All 24 isolates showed AbOmpA gene and six showed presence of Bap gene. Conclusion: This study demonstrated that isolates that produced the Bap gene were Extremely drug resistant (XDR). Biofilm formation was inhibited by Lemongrass essential oil (EO) but it did not eradicate the preformed biofilms.