Susceptibility of methicillin-resistant Staphylococcus aureus to the selenium-containing compound 2-phenyl-1,2-benzoisoselenazol-3(2H)-one (PZ51)

The growth of Staphylococcus aureus 209P was inhibited by 0.20 micrograms of 2-phenyl-1,2-benzoisoselenazol-3(2H)-one (PZ51) per ml, while strains of the family Enterobacteriaceae were more resistant to the drug. The MIC for 90% of methicillin-resistant S. aureus strains was 1.56 micrograms/ml, and the drug was bactericidal. The selenium in PZ51 was essential, since its sulfur analog (PZ25) lost the antibacterial activity.