Evaluation of the in vitro Antibacterial activity of some plant extracts against Dermatophilus congolensis isolated from skin lesions of horses

Abstract

The purpose of this research was to isolate and identify Dermatophilus congolensis from skin infections in horses in Rajasthan using conventional methods and polymerase chain reaction and to assess the efficacy of some selected antibacterial agents against D. congolensis using agar well diffusion and broth microdilution techniques. The presence of D. congolensis was confirmed by the ''Tram track'' appearance of coccoid forms in culture-stained smears as well as colony characters and biochemical tests. The existence of D. congolensis was also confirmed by the resulting 500 bp PCR amplicon. The zone of inhibition ranged from 13 mm to 21 mm, and the minimum inhibitory concentration (MIC) ranged from 1.562 mg/ml to 3.125 mg/ml for all the extracts of Eucalyptus camaldulensis when tested against D. congolensis. Zones of inhibition of 15 mm to 21 mm (MIC- 3.125 to 6.25 mg/ml) and 11 mm (MIC-25 mg/ ml) were seen for Azadirachta indica (chloroform, methanolic and ethanolic extract) and Aloe vera (methanolic extract), respectively, when tested on this pathogen. To combat the issue of antibiotic resistance, the results of this study suggest that E. camaldulensis, A. indica, and A. vera can be used or incorporated into topical antibacterial medicines.