ANTIBIOFILM ACTIVITY AND THE SYNERGISTIC EFFECT OF LEMON GRASS ESSENTIAL OIL WITH ANTIBIOTICS AGAINST A.BAUMANNII COMPLEX – A PRELIMINARY REPORT

Aparna Shivaprasad*, Beena Antony and Rekha B.

ABSTRACT

Introduction- The epidemiology and antibiotic resistance of A.baumannii have been extensively reviewed but the pathogenesis and virulence remain unclear. Biofilm formation is a well-known pathogenic mechanism in device related infections. High incidence of resistance to pharmaceutical antibiotics among microbes in hospital environment prompts the search for alternative source of antimicrobial chemicals with anti-biofilm activity. Materials and Methods- Biofilm formation and antibiofilm activity of Lemon grass essential oil [LGO] in 251 Acinetobacter clinical isolates was detected by polystyrene tissue culture plate method and modified crystal violet assay respectively. The broad-spectrum antimicrobial activity of LGO in combination with antibiotics against multidrug resistant & extremely drug resistant A.baumannii complex was also investigated. Results and Discussion- Among 251 A.baumannii isolates, 70% isolates showed biofilm formation which indicated that they were established nosocomial pathogens. About 65-79% of anti-biofilm activity was seen at the dilutions 0.625 μl/ml to 0.156 μl/ml, indicating that LGO had a significant role in inhibition of biofilm formation by A.baumannii. There was almost two fold enhancement of the antibacterial activity of the antibiotics on A.baumannii when used in combination with LGO. Conclusion- The antibiofilm activity of Lemon grass essential oil with its potentiating effect on antimicrobials by twofold might open a new avenue for determining better treatment option for A.baumannii infections as well as preventing the dissemination of nosocomial MDR & XDR A.baumannii.

Keywords: Cymbopogon flexuosus [Lemon grass], Essential oil [EO], Biofilm, Anti-biofilm activity, Synergy, MDR/XDR AB.