confers_resistance_to_antibiotic fosfomycin confers_resistance_to_antibiotic fosfomycin thiol transferase FosB3 A thiol transferase that leads to the resistance of fosfomycin in Enterococcus faecium. Contrasting FosA, FosB is dependent on the cofactor Magnesium (II) and uses either bacillithiol to open up the epoxide ring of fosfomycin. antibiotic_resistance FosB3 ARO:3002873