Repurposing of Chinese Medicine Extract against Staphylococcus Aureus: Assessing the Antibacterial and Anti-Transfer Activity of Plasmid in Drug-Resistant Bacteria.

Background: Staphylococcus aureus is one of the most frequent human infections, which triggers various infectious diseases like soft tissue infection, lethal pneumonia, endocarditis, and bacteremia. The most common pathogen responsible for simple cystitis is E.coli; however, it also causes pneumonia, bacteremia, and abdominal infections, such as spontaneous bacterial peritonitis.

Objective: Chinese medicines have been used effectively in the treatment of infectious disorders; thus, this study aimed to investigate the efficiency of Chinese medicine against S. aureus.

Methods: An extract of traditional Chinese medicine was prepared using nine compounds: tongcao, talc, red peony root, fennel, guangui, lychee core, dry sunflower, dianthus, and purslane, to evaluate its antibacterial activity against Staphylococcus aureus RN450RF.

Results: The minimum inhibitory concentration (MIC) of the Chinese medicine measured by the consecutive double dilution technique was 200g/L. The drug-resistant plasmid was transferred equally well under controlled laboratory conditions with a median conjugation frequency of 1.1x106. The maximum activity of conjugated transfer of resistant drug plasmid of E. coli CP9 (R45) was observed at 2/1 MIC (100 g/L drug concentration), 32h time interval, with a bacterial concentration 108 CFU/ml.

Conclusion: These results suggest that the secondary inhibitory concentration (1/2 MIC) of the Chinese medicine solution can promote the combination and transfer of the resistance plasmid of Chinese medicine (R45) between different strains. The drug concentration, binding time, and initial bacterial concentration have different degrees of positive promotion effects on the conjugation and transfer of drug-resistant plasmids. Traditional Chinese medicine might be a potentially huge disease management and infection control resource.