The results of a checkerboard assay using Ag NPs and cefmetazole combinations against drug-resistant N. gonorrhoeae clinical isolates.

aFICi values above 2.0 indicate antagonistic effects, values between 0.5 and 2.0 indicate additive effects, and values lower than 0.5 indicate synergistic effects.bResistant status was determined using the disc diffusion method. The following abbreviations are used: penicillin (P), cefixime (CFM), cefpodoxime (CPD), ciprofloxacin (CIP), cefmetazole (CMZ), and tetracycline (TE).cAg NPs with a diameter of 120 nm were used in assays with clinical isolates.dNot determined, as ATCC 49226 is sensitive to cefmetazole.