Widely used in microbiology laboratories for antibiotic susceptibility testing, particularly to detect methicillin-resistant Staphylococcus aureus (MRSA). It is incorporated into culture media to selectively inhibit the growth of susceptible bacteria, allowing identification of resistant strains. Due to its stability and specific activity against penicillinase-producing organisms, it serves as a key reagent in diagnostic workflows and research involving beta-lactam antibiotic resistance.