Evaluation of Antibacterial Effects of Combretum dolichopetalum Methanol Leaf Extract on some Pathogenic Bacteria

Abstract

Antimicrobial resistance (AMR) is a threat to global public health and a challenge in treating infectious diseases. This has resulted in a shift of research attention to natural substances such as medicinal plants that could be a source of developing novel drugs. Combretum dolichopetalum has been reported to have antidiarrhoeal effects in rats. In this study, the antibacterial potential of different concentrations of methanolic extract of Combretum dolichopetalum was evaluated against seven pathogenic bacteria (Escherichia coli, Bacillus cereus, Salmonella gallinarum, Aeromonas hydrophilia, Pasteurella multocida, Klebsiella pneumoniae and Shigella dysenteriae) at different concentrations using the agar well diffusion method. Antibiogram of these organisms were also carried out by the Kirby Bauer disk diffusion method. Zones of inhibition were calculated as means ± SEM. Result showed that the plant extract had significant concentration dependent antibacterial activity compared to distilled water and some known drugs (P<0.05). All concentrations showed activity against all bacteria, unlike the drugs, which had selective activity, with concentration of 400 mg/ml, showing the highest activity. Tested bacteria exhibited a high level of resistance to synthetic drugs ranging from 48% to 100%. Multi-drug resistance was also observed. S. gallinarum, B. cereus and E. coli exhibited 100% resistance to all test antibiotics. All organisms showed 100% resistance to Ampicillin-Clavulanic acid and Ceftriaxone. Results from this study show that C. dolichopetalum possesses antimicrobial activity as it inhibited growth of all test bacteria.