In recent years, vancomycin sensitivity of the Staphylococcus aureus has been dropped gradually in the world, and the medicine-resistant strains appear one after another in various countries.

AIM: to study the effect of levofloxacin, vancomycin, rifampin, azithromycin, tobramycin and chloramphenicol concentration on selection of resistant mutants of staphylococcus aureus ATCC29213.