Abstract
BACKGROUND: Rhodomyrtone is a novel plant-derived antibiotic compound originally isolated from Rhodomyrtus tomentosa leaf extract. OBJECTIVES: To evaluate the activity of rhodomyrtone against a group of MRSA strains, including isolates with reduced susceptibility or resistance to vancomycin, daptomycin, linezolid and ceftaroline. METHODS: Broth microdilution testing was used to determine the MICs and MBCs of rhodomyrtone, fosfomycin, vancomycin, daptomycin, linezolid and ceftaroline. RESULTS: ROM had an MIC(90) of 1 mg/L against 110 strains of MRSA from blood isolates as well as for all other isolates that were daptomycin resistant, VISA, VRSA or LRSA. The MBC(90) were 4 mg/L across all groups tested. Among all S. aureus groups tested the ROM MBC did not exceed 8 mg/L. CONCLUSIONS: Rhodomyrtone demonstrated excellent activity against MRSA as well as isolates with resistance or reduced activity to other anti-MRSA drugs including vancomycin, daptomycin and linezolid. Rhodomyrtone may have potential clinical utility when treating patients with infections caused by MRSA including those with reduced susceptibility to first-line anti-MRSA antimicrobial agents.