In vitro activities of aqueous and hydro-ethanolic extracts of Ocimum gratissimum on Escherichia coli ESBL, Klebsiella pneumoniae ESBL and methicillin-resistant Staphylococcus aureus

The misuse of antibiotics plays a role in increasing of antimicrobial resistance. The plants, of traditional use, then become an alternative solution to deal with this public health issue. Ocimum gratissimum L. is a widely used plant in Togo for several diseases. The objective of this work was to evaluate the antibacterial activity of the hydro-ethanolic and aqueous extracts of the leaves of this plant, by measuring the diameter of inhibition, from the method of the wells on agar medium and the determination of the minimum inhibitory concentration (MIC), and the bactericidal (MBC) concentration. For this purpose, clinical strains of Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus were used. The inhibition diameters were between 10.00 ± 0.58 and 14.67 ± 0.58 mm, and the MICs between 6.25 and 25.00 mg/ml. The results obtained show that the hydro-ethanolic and aqueous extracts have been active on all the strains tested with a bactericidal activity on the majority. However, the hydro-ethanolic extract was significantly more effective than the aqueous extract (P = 0.049) on all strains. This work has provided us a scientific basis of the use of O. gratissimum L. in our environment, particularly for the treatment of bacterial infections.   Key words: Ocimum gratissimum L, hydro-ethanolic and aqueous extracts, antibacterial activity, multi-resistant strains, Togo.