COMPARATIVE EVALUATION OF ANTIPSEUDOMONAS ACTIVITIES OF GENTAMICIN AND AQUEOUS EXTRACT OF Terminalia schimperiana ROOT BARK

ABSTRACT The author conducted a comparative evaluation of antipseudomonas activities of gentamicin and aqueous extract of Terminalia schimperiana root bark, a local remedy used in the treatment of burns wounds. Five different concentrations of gentamicin (0.625 µg/ml -10 µg/ml) and aqueous extract of Terminalia schimperiana root bark (1.25 mg/ml -20 mg/ml) were screened against Pseudomonas aeruginosa clinical isolates (n=14) and a reference culture, ATCC 10145 of P. aeruginosa, using the agar-well diffusion method. Significant differences in the minimum inhibitory concentrations (MIC) of gentamicin and aqueous extract were analysed using Analysis of Variance (ANOVA). Results revealed that 7 P. aeruginosa isolates were resistant to gentamicin at all the concentrations tested, while 8 isolates were susceptible to gentamicin at concentrations of 2.5 µg/ml, 5.0 µg/ml and 10 µg/ml, inhibition zone diameters (IZDs) ranging from 15.3 mm to 23.0 mm. All the isolates were susceptible to the aqueous extract, IZD values ranging from 12.0 mm to 22.5 mm. MIC values for gentamicin ranged from 0.2 µg/ml to 1.995 µg/ml, while MIC values for aqueous extract ranged from 0.054 mg/ml to 1.622 mg/ml. Analysis of variance (ANOVA) revealed no significant difference (P=0.32) in the MIC values of gentamicin and the aqueous extract. The aqueous extract inhibited 7 isolates resistant to gentamicin, suggesting that it possesses better antipseudomonas properties than gentamicin. The author recommend that the aqueous extract of T. schimperiana root bark be subjected to more detailed studies in view of its potential in the healing of wound and burns infections caused by resistant bacteria