Synergetic Effects of Plant Extracts and Antibiotics on Vibrio cholerae O1 Strains Isolated From Clinical Specimens

The objective of this study was to evaluate in vitro synergy of extracts from Picralima nitida, Cylicodiscus gabunensis, Cassia arereh and Trichilia emetica and known antimicrobial agents against clinical isolate of vibrio cholerae. The in vitro antibacterial activity of plant-extracts was evaluated alone and in combination with standard antibiotics against Vibrio cholerae using disc-diffusion and microdilution method. Only antibiotics acting by inhibiting proteins synthesis shown strong bactericidal activity with inhibition zone diameter ranging from 11 ± 0.0 to 26 ± 0.6 mm. we also noticed that methanolic extract of Cassia arereh and Trichilia emetica and ethyl acetate extract of Cassia arereh contain bioactive compounds. These extracts were effective anticholeric agents with MIC ranging between 12.207 and 97.656 µg/ml and MBC between 48.828 and 781.25 µg/ ml. Cassia arereh extract showed the greatest activity with MIC and MBC values of 12.207 and 48.828 µg/ ml respectively. Synergism was observed between antimicrobial agents and the best anticholeric plant-extract with significant reduction in the MICs of antibiotics against the strains tested. Administration of both compounds together resulted in an MIC ranging from 0.078 to 10 µg/ ml which represents a 2 to 16-fold reduction in the MICs of the antibiotics tested alone. This change in MIC was noticed even with antibiotics showed weak antibacterial activity.