Antibacterial and antiadherence properties of the leaves of Ficus thoninngii blume on Acinetobacter baumannii

Abstract

Background: The ability of Acinetobacter baumannii to adhere and persist in any environment has aided its persistence in hospital environments. Ficus thonningii Blume has antimicrobial abilities and may halt the attachment of microorganisms to air-liquid surfaces.

Objective: To investigate the antibacterial and antiadherence properties of the leaves of Ficus thonningii on A. baumannii.

Materials and Methods: Antibiogram of twenty-three clinical isolates of A. baumannii including a typed strain was determined using disc-diffusion method. Antimicrobial activities of the leaf extracts and fractions of Ficus thonningii were screened by agar-well diffusion. The minimum inhibitory concentration (MIC) was determined by agar-dilution. The ability of the organism to adhere to air-liquid surface and form pellicle, and the ability of the extracts to inhibit the pellicles formed were investigated. Pellicle forming strains of E. coli ATCC 35218 and A. baumannii 111A were used as controls. One-way ANOVA was used to compare the optical densities of the pellicles formed.

Results: At 50 mg/mL, the inhibition zone diameter produced by ethyl acetate, methanol and n-hexane extracts ranged from 0-15 mm with ethyl acetate extract having the highest activity. The MIC ranged from 0.039-1.25 mg/mL, 0.039-20 mg/mL and 1.25-20 mg/mL for ethyl acetate, methanol and hexane extracts respectively while the MBC ranged from 5-20 mg/mL, 1.25-20 mg/ml and ≥20 mg/mL also respectively. Pellicle formation was observed in 62.0 % of the bacterial isolates. There was a slight reduction in the pellicles formed at 12.5 mg/mL concentration of the extracts.

Conclusions: The study has shown that Ficus thonningii can be used in the management and treatment of infections caused by A. baumannii. It also has the ability to inhibit pellicles formed by the organism at increased concentrations.

Keywords: Acinetobacter baumannii, Ficus thonningii, Antibacterial, Antiadherence, Pellicle