Abstract

Hospital-acquired infections are caused by multidrug-resistant Enterococcus (E.) species, especially E. faecalis and E. faecium, which are zoonotic bacteria and pose a significant public health challenge. This study aimed to identify multidrug-resistant Enterococcus isolates and evaluate the antibacterial activity of Rosmarinus officinalis (R. officinalis) extract against E. faecalis and E. faecium. Fifty urine and stool samples were collected from hospitalized patients. Four multidrug-resistant strains—E. faecalis 6E, 7B, 10D, and E. faecium 15E—were identified by polymerase chain reaction (PCR) with universal primers (8F and 1492R) targeting the 16S rDNA gene to confirm their identity as Enterococcus species. The antibacterial efficacy of R. officinalis extract was assessed using disk diffusion and minimum inhibitory concentration (MIC) determination. High-Performance Liquid Chromatography (HPLC) analysis was conducted to identify phenolic bioactive compounds in R. officinalis. The extract demonstrated significant antibacterial activity, with MICs of 25 mg/mL and 30 mg/mL for E. faecalis and E. faecium, respectively. HPLC revealed phenolic compounds such as rosmarinic acid, caffeic acid, and ferulic acid, likely contributing to the antimicrobial properties. The R. officinalis extract could be a promising natural antimicrobial agent against multidrug-resistant Enterococcus species. Compounds such as rosmarinic acid, caffeic acid, ferulic acid, apigenin-7-glucoside, syringic acid, and p-hydroxybenzoic acid show potential as safer, environmentally friendly alternatives to traditional antibiotics, aiding in the fight against rising antibiotic resistance.