Isolation of major bacterial species associated with equine skin wounds and in-vitro antibacterial activities of selected medicinal plants

Wounds on the skin are a common health issue affecting working equines. This study aimed to evaluate the in-vitro antibacterial properties of crude methanolic extracts from selected medicinal plants against pathogens isolated from equine skin wounds in Merti district. Agar well and disc diffusion tests were used to determine the mean zone of inhibition, while broth dilution methods were used to determine the minimum inhibitory concentrations and minimum bactericidal concentrations (MBCs), further confirming the potent antibacterial effects of the selected medicinal plant extracts. One way analysis of variance was used to compute the mean zone of inhibition (mm ± SEM) using SPSS version 20. The results showed that Staphylococcus aureus was the most frequently isolated bacterial pathogen. The medicinal plants Zingiber officinale (ginger), Allium sativum (garlic), Croton macrostachyus, and Solanum incanum exhibited significant antibacterial activity against S. aureus, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae. On agar well diffusion method, the highest and lowest zone of inhibition was recorded in C. macrostachyus (28.0 ± 1.2 mm for S. aureus standard strain) and Z. officinale (12.7 ± 0.7 mm for K. pneumoniae wound isolate), respectively at 780 mg/mL concentration. Similarly, C. macrostachyus showed the highest (28.3 ± 0.9) zone of inhibition using the disc diffusion test for S. aureus standard strain. In combined extracts, the highest zone of inhibition was found against standard strain of S. aureus with Croton macrostachyus + Zingiber officinale (33.0 ± 0.6), followed by both Allium sativum + Zingiber officinale and Allium sativum + Croton macrostachyus at 32 ± 1.2 mm at 780 mg/mL concentration. The minimum inhibitory concentration ranged from 12.18 mg/mL for A. sativum (against standard S. aureus) to 390 mg/mL for S. incanum (against P. aeruginosa), while MBC ranged from 24.38 mg/mL for A. sativum (against S. aureus and E. coli) to > 390 mg/mL for S. incanum against K. pneumoniae and P. aeruginosa. The findings demonstrate the potential of these natural resources as alternative or complementary treatments for managing bacterial infections associated with equine skin wounds, which is particularly relevant in the context of the growing global challenge of antibiotic resistance, and provide valuable baseline information for future in-vivo investigations and the potential development of herbal-based wound management strategies in equine veterinary practice, warranting further in-vivo studies.