Antibacterial Properties of an Aqueous Extract of Solanum torvum (Solanaceae) on a Few Multidrug Resistant Bacterial Strains to Common Antibiotics

This study aimed to evaluate the antibacterial activity of the aqueous extract of Solanum torvum leaves (EASt) on multidrug-resistant bacterial strains to common antibiotics. This plant is used in traditional medicine against diarrhoea. Solid agar diffusion and liquid dilution methods were respectively used to assess the sensitivity of bacterial strains to EASt and to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Tests performed on ten (10) bacterial strains, isolated from various biological products, showed that Staphylococcus aureus 234 UB/17 and Escherichia coli 135 UB/17, were significantly sensitive to EASt, with a higher sensitivity for the latter strain. This sensitivity was shown by an inhibition of bacterial growth in solid agar and liquid medium, by a decrease in turbidity caused by EASt sensitive germs growth as the concentration of this plant extract increased (25 to 100 mg/ml). This demonstrate that EASt is an antibacterial substance. Thus, treated with EASt at a dose of 100 mg/ml, the MICs of S. aureus 234 UB/17 and E. coli 135 UB/17 were 6.25 and 12.5 mg/ml respectively, and the MBCs were 25 and 50 mg/ml respectively. The ratio of these bactericidal parameters (MBC/MIC) equaled to four (4) for these two bacterial strains, indicating that EASt is bactericidal for these bacterial strains. The antibacterial and bactericidal properties of EASt on multiple antibiotic resistant germs could justify the use of this plant in traditional medicine for the treatment of some bacterial infections causing diarrhoea