Phytochemical Profiling of Aqueous Extracts of Medicinal Plants and their Activities against Multi-resistant Bacteria

Abstract

Acintobacter baumannii and Klebsiella pneumoniae are among the most critical pathogens gaining attention. These microorganisms continue to develop resistance thereby leading to various nosocomial infections which are difficult to treat. This study determined the resistance pattern of A. baumannii and K. pneumoniae and evaluates the activities of bio-molecules from selected plants against these clinical isolates. Fifty samples of A. baumannii and K. pneumoniae, which were isolated from different clinical samples were collected from different hospitals at Ogbomoso and then confirmed by their biochemical features to ascertain their identity. The antibacterial susceptibility pattern was determined by Kirky-Bauer disk diffusion method and the results were compared with the CLSI standard. Exactly, 500µL (0.5mL) of aqueous crude extract was used to evaluate the antibacterial efficacy on bacterial isolates by agar well diffusion method while gentamicin (10μg) was used as control. The qualitative phytochemical analysis of the bio-molecules in selected plant extracts was performed using standard methods and bioactive constituents were analyzed by Gas Chromatography-Mass Spectroscopy analysis. Forty-two (42) (84%) from the total of 50 bacterial isolates collected were confirmed to belong to Acinetobacter and Klebsiella genera. Total resistance (100%) was observed with Ampiclox (ACX) and cefuroxime (CXM) while ceftazidime (CAZ) showed 92% resistance to antibiotics used. Gentamicin (GEN) and nitrofurantoin (NIT) were found to be an effective antimicrobial agent with 72% susceptibility each. A. baumannii (UITH 8, UITH13 and UITH15) showed highest resistance each with 84.6% resistance to all antibiotic used, while K. pneumoniae (UITH2) showed 100% resistance. HCE and CCE were found to consistently show the strongest efficacy in a range of 4–10mm. K. pneumoniae, K. oxytoca and A. baumannii exhibited high inhibition zones up to 10mm with HCE and CCE. The aqueous hot and cold clove extracts were found to possess all metabolites at varying degree, with the exception of quinones which was absent in all samples. This study supports the potential role of medicinal plants as promising alternatives source of antimicrobials. It is recommended that the bioactive compounds present in the plant extracts should be purified and studied for their antimicrobial actions.