BACKGROUND AND AIM

is a zoonotic pathogen with significant public health and economic implications. Its ability to tolerate environmental stress and regulate virulence through quorum sensing contributes to its persistence and pathogenicity. and its bioactive compound rhodomyrtone have demonstrated antimicrobial properties against Gram-positive, multidrug-resistant bacteria. This study aimed to evaluate the effects of these agents on quorum sensing inhibition and stress tolerance in and , providing insights into their potential as alternative antimicrobial strategies.

MATERIALS AND METHODS

The anti-quorum sensing activity of extracts was assessed using as a bioindicator. In addition, the effects on swarming motility were evaluated. Stress tolerance in was examined by subjecting treated cells to acidic (pH = 5.0), alkaline (pH = 9.0), osmotic (7.5% NaCl), heat (43°C), and oxidative (1 mM HO) stress conditions. The survival rates were determined through colony-forming unit (CFU) counts following treatment with rhodomyrtone and ethanol leaf extracts.

RESULTS

The ethyl acetate fraction of leaf extract exhibited the highest violacein inhibition, followed by the ethanol extract. At 256 μg/mL, these extracts permitted colony formation but inhibited its swarming motility. Regarding stress tolerance, no surviving cells were detected under any stress condition after 3-6 h of treatment with 2 × minimum inhibitory concentration (MIC) (1 μg/mL) of rhodomyrtone. In addition, 4 × MIC (128 μg/mL) of the ethanol leaf extract inhibited pathogen survival under all tested stress conditions except for alkaline and oxidative stresses.

CONCLUSION

The findings suggest that extracts and rhodomyrtone effectively inhibit quorum sensing and stress tolerance, offering a promising alternative antimicrobial approach. These compounds could be utilized in veterinary medicine and food safety to mitigate zoonotic pathogen contamination and combat antibiotic-resistant infections.