Susceptibility Studies of Vancomycin Resistant Staphylococcus aureus (VRSA), Extended ?-lactamase Producing Escherichia coli and P. falciparum to Ethylacetate Extract of Endophytic Fungal Metabolites from Annona senegalensis

Abstract

Search for novel compounds can impact positively in the development of action plans in the control of existing and emerging antimicrobial drug-resistance (ADR). This study, aimed at assessing the susceptibility of vancomycin resistant Staphylococcus aureus (VRSA), extended ?- lactamase (ES?L) producing Escherichia coli and Plasmodium falciparum to ethyl acetate extract of secondary metabolites of endophytic fungi isolated from the leaves and root of Annona senegalensis Pers. Seven endophytic fungi were isolated from cultured, freshly collected root and leaves of A. senegalensis. Six (Root(RT)1, Root (RT)2, Root(RT)3, Leaf-Blade(LB)1, Mid-Rib(MR)1 and Mid-Rib(MR)2) out of the seven isolates whose toxicity profiles had been ascertained in our previous study were selected for antibacterial and antimalarial studies. The antibacterial activities of the endophytic fungal extracts were tested using the agar well diffusion technique. The activities were tested against VRSA and ES?L E. coli and ciprofloxacin- (5 µg) was used as the positive controls. In vitro anti-malarial activity was also carried out with the extracts. The result showed that out of the six isolates, RT1 metabolite had marked activities against ES?L E. coli and P. falciparum. Similarly, RT2, had an impressive activity against VRSA, ES?L E. coli and P. falciparum. The highest concentration of RT2 gave 58 % inhibition of the parasite whereas that of the control was 66 %. This impressive susceptibility of VRSA, ES?L E. coli and P. falciparum to these fungal metabolites call for further studies on these metabolites to purify and elucidate the bioactive component of each compound.