Exploring the Antibacterial Potential of Vitex doniana and Jatropha curcas Leaf Extracts against Multidrug-Resistant Pseudomonas aeruginosa from Clinical and Environmental Sources

Multidrug-resistant Gram-negative bacteria remain of significant global health and economic concern, affecting both developed and developing nations, including Nigeria. Among these, Pseudomonas aeruginosa is one of the most challenging to manage due to its extreme resistance to multiple antibiotics and its association with a high-rate nosocomial infections, thus creating a significant burden in the clinical world. These gaps necessitate the search for new and more effective treatment options for multidrug-resistant Pseudomonas aeruginosa. This study evaluates the antibacterial properties of Vitex doniana and Jatropha curcas leaf extracts against clinical and environmental multidrug-resistant P. aeruginosa strains. Chloroform was used for extraction, and subsequent qualitative and quantitative phytochemical screening assays were performed. One hundred and fifty clinical and environmental samples were collected for the isolation of P. aeruginosa. Resistance levels and the antibiotic susceptibility patterns were tested using the standard disc diffusion bioassay. The expression levels of multidrug resistance genes AcrA, blaOXA-23, and blaVIM were analyzed to identify strains resistant to multiple drugs. An in vitro bioassay was employed to determine the antimicrobial potential of the extracts, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined. Phytochemical screening revealed the presence of tannins, saponins, alkaloids, flavonoids, phenols, terpenoids, quinones, phytosterols, and phlobatannins in the extracts with an unusually high concentration of phenolic compounds. Eleven highly multidrug-resistant P. aeruginosa strains were successfully grown, primarily from wound swab cultures and clinical samples. All strains carried at least two of the examined resistance genes (blaTEM, blaSHV, and CTX-M). The in vitro antimicrobial activity bioassay confirmed that Jatropha curcas extract was more potent than the Vitex doniana extract, which was weaker against some strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Jatropha curcas extract were as low as 0.125 mg/ml. Overall, the findings suggest that Jatropha curcas extract exhibits potent antibacterial activity and is a potential therapeutic agent for treating multidrug-resistant P. aeruginosa infections.