Antibacterial and anti-biofilm activity of plumbagin against multi-drug resistant clinical bacterial isolates
Mohammad A. Alfhili, Irfan Ahmad, Yasser Alraey, Abdulaziz Alangari, Taha Alqahtani, Ayed A. Dera
Abstract
<h3>Objectives:</h3> To evaluate the antibacterial activity of plumbagin (PGN) against multidrug resistance (MDR) clinical isolates. <h3>Methods:</h3> This study was carried out at the Department of Clinical Lab Sciences, King Khalid University from October 6, 2021 to December 14, 2021. We investigated the antibacterial and anti-virulence activity of PGN against MDR Gram-negative (<i>Escherichia coli</i>, <i>Klebsiella pneumoniae</i>, <i>Salmonella Typhi</i>, and <i>Pseudomonas aeruginosa</i>) and Gram-positive (<i>Staphylococcus aureus [S. aureus]</i>, <i>Staphylococcus saprophyticus [S. saprophyticus]</i>, <i>Streptococcus pyogenes</i>, and <i>Enterococcus faecalis</i>) clinical bacterial isolates. Agar well diffusion, microdilution assay, colony count method, biofilm formation, and time-kill kinetics were employed to probe the MIC, MBC, and anti-virulence activity of PGN. <h3>Results:</h3> Plumbagin inhibited the growth of all tested isolates, with <i>S. saprophyticus</i> exhibiting the highest sensitivity. MIC values ranged from 0.029 to 0.117 µg/mL whereas MBC ranged from 0.235 to 0.94 µg/mL, with 79% to 99% growth inhibition. Moreover, all tested isolates showed a marked decrease in biofilm formation, with <i>S. saprophyticus</i> and <i>S. aureus</i> being the most sensitive. <h3>Conclusion:</h3> Plumbagin is a stand-alone, broad spectrum antibacterial with promising potential against the rising threat of antimicrobial resistance.