Antimicrobial Activity of Vernonia amygdalina Leaves Aqeuous Extracts against Multidru-resistant Bacterial Isolates from Poultry Chickens in Bauchi Metropolis

Abstract

Background: The rise of Multidrug-resistant (MDR) bacteria in poultry due to excessive antibiotic use presents a serious public health concern, especially in regions like Bauchi Metropolis where poultry farming is widespread. There is increasing interest in exploring natural plant-based alternatives to antibiotics. Vernonia amygdalina (bitter leaf) is a medicinal plant traditionally used for its antimicrobial properties, but its effectiveness against MDR bacteria from poultry sources remains under-researched. Aim: The study aims to evaluate the antimicrobial activity of aqueous extracts of Vernonia amygdalina leaves against Multidrug-resistant bacterial isolates obtained from poultry chickens in Bauchi Metropolis. Place and Duration of Study: This study was carried out in the Abubakar Tafawa Balewa University (ATBU), Bauchi, Nigeria, in a period extended from August 2024 to March 2025. Methodology: Cloacal rectal swab samples of poultry birds were collected using a swab stick. The samples were immediately transported and processed in the Microbiology laboratory at Yelwa Campus. Bacterial identification was performed using standard microbiological techniques, including Gram staining, selective media culture, and microscopy. Antimicrobial susceptibility was evaluated using the Kirby-Buer disc diffusion method, while the effects of V. amygdalina leaf extracts were tested using aqueous extractions. Results: Eight bacterial species were identified, with Escherichia coli being the most prevalent (26.6%), followed by Staphylococcus aureus (14.4%) and Streptococcus pyogenes (14.4%). Antibiotic susceptibility testing revealed high resistance rates to commonly used antibiotics, with 111 isolates classified as MDR. E. coli exhibited the highest MDR prevalence (31.5%), showing significant resistance to azithromycin, amoxicillin, ceftriaxone, and ciprofloxacin. The antimicrobial susceptibility testing of V. amygdalina extracts demonstrated inhibitory effects on most MDR isolates, with minimum inhibitory concentrations (MIC) of 50.0 mg/ml for the aqueous extract. However, 28 isolates (25.2%) remained resistant to the extracts Conclusion: The study reveals broader concern of antibiotic resistance among poultry-associated bacteria. It also shows Vernonia amygdalina possesses antimicrobial potential and could serve as an alternative to synthetic antibiotics for managing MDR bacterial infections in poultry. Further research is required to standardize its application and explore additional treatment options, as some isolates exhibited resistance to Vernonia amygdalina extracts.