Nitrocefin assay with live MRSA. MRSA growth curves were constructed to identify the log phase (5-7 hours of incubation at 37 °C after 1:1,000 dilution of an overnight culture yielded exponential growth). Bacteria were grown under different conditions (with or without antimicrobials/chemicals) for 7 hours. For uninduced samples, ~5e 5 CFU/mL of MRSA was incubated with CA-MHB and one of chemical 1, 2, or 3 at a final concentration of 50 μM. A v:v equivalent DMSO was used as control. For samples induced to produce penicillinase, ~5e 5 CFU/mL of MRSA was incubated with 64 μg/mL penicillin G in CA-MHB and chemical at a concentration of 50 μM. Again, DMSO was used as control.