Rhodomyrtone: a new anti-Staphylococcus aureus agent against resistant strains

Abstract

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 MIC90 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 MBC90 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.