In vitro activities of the methanolic extracts and fractions of Bridelia ferruginea Benth on clinical isolates of multidrug resistant gram-negative bacteria

Abstract

Introduction: Antimicrobial resistance is of major public health concern. There is paucity of data on antimicrobial activity of the fractions and sub-fractions of methanol extract of the stem bark of Bridelia ferruginea Benth, Phyllanthaceae on multi-drug-resistant Gram negative bacteria. We explored their susceptibility to fractions of this plant extracts. Method: Methanolic extract and N-hexane, Dichloro-methane (DCM) and Ethyl acetate (EtoAc) fractions of the dried stem bark of Bridelia ferruginea, were tested against twenty multi-drug-resistant GNB clinical isolates using Agar diffusion and Broth-dilution methods. Results: The zone of inhibition of extracts ranged between 0-22mm, comparable to 0-28mm observed for Imipenem and Ciprofloxacin. The EtoAc fraction exhibited the highest antimicrobial activities against Klebsiella pneumoniae, Acinetobacter baumanni and others. Conclusion: Most of the antimicrobial activities of Bridelia ferruginea Benth reside in the ethyl-acetate fraction and further study to isolate the active compound(s) is advocated and desired for development of new drugs against MDR.