Fig. 1.

Parent S. aureus isolates give rise to resistant phenotypes against Nigella sativa (NS) essential oil and/or antimicrobials. Resistance to NS was evidenced by colony growth within the inhibition zones of NS discs (20 µL/disc). To assess combined resistance, bacteria were first exposed to NS and after 30 min, NS disc removal and antimicrobial disc placement were done. Regardless of whether resistance developed against NS alone or the NS/antimicrobial combinations (DO and DA), the resulting colonies displayed unusual traits; they were transparent, had intact margins, varied in size, and lacked their typical pigmentation.