Susceptibilities of Clinical Bacteria Isolates to Two Ethanolic Extracts of Terminalia schimperiana

Background/Objectives: The authors evaluated the in vitro antimicrobial effects of the ethanolic extracts of Terminalia schimperiana root bark and leaves, which are used locally in the treatment of burns wounds, bronchitis and dysentery. Methods: Five different concentrations of the crude extracts (1.25 mg/ml to 20 mg/ml) were screened against Staphylococcus aureus (n=2), Escherichia coli (n=2), Pseudomonas aeruginosa (n=4), Salmonella typhi (n=1), and a reference culture, ATCC 10145 of P. aeruginosa, using the agar-well diffusion method on Mueller-Hinton agar. Significant differences in the minimum inhibitory concentrations (MIC) of the extracts were analyzed using Analysis of Variance (ANOVA). Gentamicin was included as a standard antibiotic. Phytochemical analysis of the root bark extract was performed. Results: The results revealed that the extracts exhibited varying but significant activities against S. aureus, P. aeruginosa and S. typhi but not to E. coli. Inhibition zone diameters (IZD) ranged from 17.2 mm to 10.0 mm. MIC values ranged from 0.058 mg/ml to 2.089 mg/ml. Inhibition zone diameters of gentamicin ranged from 21.8 mm to 10 mm. However, two P. aeruginosa isolates were resistant to gentamicin at all the concentrations tested. Conclusion: The results seem to support the efficacy of the extracts in the folkloric treatment of burns wounds, and bronchitis and dysentery respectively, and show that the in vitro antibacterial activities of the extracts are comparable with that of gentamicin. The authors recommend that the extracts be subjected to more detailed studies in view of their potentials in the treatment of infections caused by resistant bacteria