Evaluation of Antimicrobial Activity of Methanol Extracts of three Selected Lower Plants Against Wound Pathogens

Background: The resistance of bacteria to conventional antibiotics has been of great concern worldwide. This has prompted the need to explore alternative natural sources, such as plants, for safer, cheaper and more effective therapies. The use of medicinal plants in wound care is a common practice in traditional medicine. Therefore, the methanol extracts of three lower plants (Nephrolepis biserrata (Fam: Nephrolepidaceae), Platycerium stemaria (Fam: Polypodiaceae), and Platycerium angolense (Fam: Polypodiaceae)) were assessed for their antimicrobial activities against some wound pathogens. Methods: Wound swabs were collected from twenty patients presenting with wounds at the University Health Centre in Ile-Ife, cultured and the bacteria isolated were identified using conventional biochemical tests. Antimicrobial Susceptibility Test (AST) was carried out on Mueller-Hinton agar using the disk-diffusion method. The Minimum Inhibitory Concentrations (MIC) of methanol plants' extracts against the identified bacteria were determined using the broth micro-dilution technique. Results: Among the 20 bacteria isolated, 55% and 45% were Gram-positive and Gram-negative, respectively. The most common was Micrococcus luteus (25%), then Staphylococcus aureus (20%), Pseudomonas aeruginosa (15%), Bacillus spp. (10%), Enterobacter aerogenes (10%), Proteus mirabilis (10%), Escherichia coli (5%), and Klebsiella pneumoniae (5%). The methanol extract of N. biserrata showed the highest antimicrobial activity. However, all the isolates that were resistant to azithromycin antibiotic were not susceptible to all the extracts of the 3 selected plants. Conclusion: N. biserrata and Platycerium spp. leaves could be useful in the management of wound infections as they exhibited antimicrobial activity against isolated wound pathogens. The results from this study support the ethnobotanical use of the plants in wound treatment