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.