Antibacterial Activity of Ocimum tenuiflorum against Drug Resistant Bacteria Isolated from Raw Beef.

Abstract

Recent empirical evidence has acknowledged raw meat, particularly beef, as a significant reservoir for diverse foodborne pathogens and drug-resistant strains, posing severe threat to consumer health. This study aimed to isolate and identify drug-resistant bacteria from raw beef samples, obtained from different butcher shops in Khulna city, Bangladesh, as well as, to determine their susceptibility pattern against Ocimum tenuiflorum extracts. Raw beef samples were randomly collected from various butcher shops, followed by the initial isolation of thirty pure bacterial isolates. Later, 16S rRNA gene amplification and analysis identified twelve distinct bacterial species from those isolates. The antimicrobial susceptibility test results revealed ten of the isolates, including Klebsiella pneumoniae, Aeromonas veronii and Enterobacter hormaechei, to exhibit multidrug resistance pattern. Amoxicillin, nitrofurantoin, and flucloxacillin were found to be ineffective against most isolates. However, the ethanolic extracts of O. tenuiflorum were found effective in inhibiting the growth of eight species at three different concentrations. Subsequent HPLC analysis of O. tenuiflorum reported the presence of five secondary metabolites epicatechin, syringic acid, rutin hydrate, p-coumaric acid, and myricetin as potent contributors to the observed antimicrobial activity. Lastly, in silico binding interaction simulations of the secondary metabolites against five relevant targets predict syringic acid and myricetin to have effective antibacterial properties, primarily mediated by better binding affinity and molecular interactions. Thus, this study identified diverse drug-resistant bacteria in raw beef and provided novel insights into the antibacterial properties of O. tenuiflorum extracts.