(184ad) Toxic to Treatment: Bioprospecting in Battery Waste Rhizospheres for Novel Therapeutics Against High Priority Antibiotic-Resistant Pathogens

The rate of antibiotic resistance on the rise has urgently called for a radical approach to developing sustainable solutions to mitigate it. In particular, two critical pathogens, Pseudomonas aeruginosa (strain ATCC 27853), and Acinetobacter baumannii (strain ATCC-BAA-1605), have been classified as extremely drug-resistant (XDR) by the World Health Organization (WHO), subsequently overwhelming contemporary treatments. Consequently, this study hypothesised that rhizospheric microbiota of plants tolerant to metal-laden environments must have demonstrated resilience through their survival under nutrient limiting conditions and extreme environmental stress, and therefore might secrete antimicrobials during competitive exclusion that are potent enough to inhibit the growth of these pathogens. To investigate our hypothesis, this study evaluates the secretion of strong antimicrobials from heavy-metal-contaminated rhizospheres using a novel method that induced unnatural environmental stress on them. The success of this method was indicated by the experiential inhibition (≤ 19 mm) of 3.0 × 10^14 CFU/mL estimates of both multi-drug-resistant pathogens, during Agar Well Diffusion tests using crude extracts of the secondary metabolites. Moreover, pathogens were more responsive to exudates of microbiota from environmentally stressed rhizospheres than their counterparts from an organic rhizosphere. The components of the extracted secondary metabolites were purified and separated using a generic fractionation using HPLC-MS/UV, where a number of compounds demonstrated activity against the pathogens in the form of halos of inhibition. Ultimately, the novelty of the metabolites secreted needs to be validated through UPLC-MS and NMR, and the IC50 needs to be calculated to warrant further investigations on their pivotal contributions to biomedicine and biopharmaceutics.

Keywords: Antimicrobial; Antibiotics resistance; Antibiotics susceptibility; Competitive exclusion; Environmental stress; Rhizospheric microorganisms