Gold nanoparticles (AuNPs) have been previously shown to induce gut dysbiosis during colitis in mice, but the underlying mechanism is not clear yet. Here, we evaluated the effects of AuNPs (5 nm diameter, coated with tannic acid, polyvinylpyrrolidone or citrate) on HO accumulation and pathogen antagonization by an intestinal strain of under aerobic cultural conditions. AuNPs (0.65 μg/mL) reduced over 50% of HO accumulation by , and significantly inhibited the antagonistic action of on growth of four foodborne enteric pathogens, i.e. serovar Typhimurium, , , and in associative cultures.