Susceptibility of selected multi-drug resistant clinical isolates to leaves of Carpolobia lutea

Abstract

Background: The decline in the production of new effective antibiotics coupled with the constantly evolving antimicrobial resistance remains a public health concern.This study thus evaluated the antibacterial and antifungal effects of the ethanolic, n-hexane and hot aqueous extracts of Carpolobia lutea leaves.

Methods: The extracts were tested using agar well diffusion method against selected clinical isolates: Pseudomonas aeruginosa, Salmonella typhi, Escherichia coli, Staphylococcus aureus and Candida albicans. Antibiogram profile of the isolates were deduced by disc diffusion method.

Results: Multi-drug resistance was confirmed in all bacteria with a notable pandrug resistance in Pseudomonas aeruginosa. Ofloxacin, Erythromycin and Gentamicin were effective on two or three organisms, notably on Salmonella typhi and Escherichia coli. The preliminary antibacterial assay marked the efficacy of
the ethanol and n-hexane extracts except on E. coli, with zero activity for hot water extracts at the stock concentration (200 mg/ml). Pseudomonas aeruginosa and Candida albicans were susceptible to lesser concentrations of the ethanol extracts at 5 mg/ml and 25 mg/ml respectively. None of the isolates showed sensitivity to lesser concentrations of n-hexane extract. Carpolobia lutea leaves proved to be effective over the use of antibiotics in inhibiting the activity of Pseudomonas aeruginosa which was resistant to the latter. The Minimum Inhibitory concentration of the ethanolic extract was considerably low (≤5mg/ml for P. aeruginosa and 25mg/ml for C. albicans). However, there was no Minimum Bactericidal concentration for the extracts against the clinical isolates.

Conclusion: Carpolobia lutea shelters bioactive components with pharmacological potentials that could show efficiency in the treatment of bacterial infections.

Keywords: Carpolobia lutea, antifungal, antibacterial, multi-drug resistance