Combined Antimicrobial Effects of Lactiplantibacillus plantarum-Derived Biosurfactant and Supercritical CO2-Extracted Rosmarinus officinalis Against Multidrug-Resistant Staphylococcus aureus

The global prevalence of antibiotic-resistant bacteria, such as Staphylococcus aureus, presents a substantial challenge to public health, necessitating the development of innovative therapeutic strategies to combat these infections. This study examined the synergistic effects of a biosurfactant (BS) derived from Lactiplantibacillus plantarum and a novel extract from Rosmarinus officinalis (RoME) obtained through supercritical CO2 extraction against S. aureus sourced from the microbiology laboratory at King Salman Hospital in Ha’il, Saudi Arabia. Antibacterial efficacy was determined using minimum inhibitory concentration (MIC) assays, assessments of bacterial membrane damage, and qRT-PCR analysis of genes associated with antibiotic resistance. The findings revealed that the S. aureus strain exhibited resistance to multiple antibiotics with a resistance score of 0.44. RoME and BS demonstrated MICs of 0.125 mg/mL and 0.5 mg/mL, respectively. The assays indicated significant bacterial membrane damage and reduced expression of the norA, mdeA, and sel genes, which are implicated in resistance and virulence, respectively. The combination of BSs with plant extracts may provide innovative approaches for treating infections caused by multidrug-resistant bacteria, highlighting the potential of probiotic-derived BSs in combination with plant extracts.