Study of Efflux Pumps in Multi-Drug Resistant Bacteria and the Investigation of Plant Extracts as Potential Inhibitors

Antimicrobial resistance (AMR) is a rising global health concern, as bacteria continue to develop resistance to antibiotics through time. A very common resistance process in multidrug-resistant (MDR) bacteria is the efflux pump system that pumps antibiotics and other toxic substances out of the bacterial cell. Both gram-positive and gram-negative bacteria have efflux pumps, with gram-negative organisms having all types of efflux pumps. The chemical efflux pump inhibitors (EPIs) exist, but toxicity at higher doses restricts their utilization, emphasizing the search for plant-based alternatives. The objective of the study was to determine the presence of efflux pumps in MDR strains of Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterobacter cloacae using the Ethidium Bromide (EtBr)-agar cartwheel assay and investigate the role of certain Indian plants in inhibiting the efflux pump activity. The extracts obtained from the plants such as Tagetes erecta (Marigold), Mangifera indica (Mango) and Allium sativum (Garlic) were screened for their potential as a source of natural EPIs. Antibacterial action of these extracts was evaluated using agar cup and broth dilution assays to determine the Minimum inhibitory (MIC) and bactericidal (MBC) concentrations of the potential extracts. The study illustrated that Garlic and Marigold plant extracts have the potential to be employed as MDR bacterial efflux pump inhibitors.