The emergence of multi-drug resistant microbes necessitates a continuous search for newer, effective antimicrobial agents. The crude methanol leaf extract of Vernonia glaberrima was screened for its antimicrobial activity against pathogenic microorganisms including Methicillin resistant Staphylococcus aureus, Vancomycin resistant enterococci, Listeria monocytogenes, Staphylococcusau reus, Helicobacter pylori, Campylobacter fetus, Proteus vulgaris, Pseudomonas fluorescens, Candida tropicalis and Candida stellatoidea using agar diffusion and broth dilution methods. The result of the susceptibility test showed the extract (400μg) inhibited the growth of Methicillin-resistance S. aureus, Vancomycin resistant enterococci, S. aureus, H. pylori, P. fluorescens and C. stellatoidea with mean zone of inhibition range of 18 to 29 mm; the most susceptible organism was S. aureus (29 mm) and the least was the fungus, C. stellatoidea (18 mm). No activity was observed against L. monocytogenes, C. fetus, P. vulgaris and C. tropicalis. Sparfloxacin (5µg/ml) the standard antibacterial drug, had inhibitory activity against all the test organisms except H. pylori, P. flourescens, C. tropicalis and C. stellatoidea while the standard anti-fungal drug, Fluconazole (5µg/ml), showed activity only on the two fungi species, C. tropicalis and C. stellatoidea. The Minimum inhibitory concentration (MIC) and the minimum bactericidal/fungicidal concentration (MBC/MFC) ranges for the extract were 5 to 20 mg/ml and 10 to 40 mg/ml, respectively. The results of this study suggest that the methanol leaf extract of V. glaberrima contains bioactive principles that have good antibacterial and antifungal activity, validating the antimicrobial use of the plant in traditional medicine.
Key words: Vernonia glaberrima, extract, antimicrobial, MIC, MBC, evaluation.
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