The antibacterial activity was measured in both Gram-positive and –negative strains, including clinical isolates of multidrug-resistant pathogens. The cytotoxic effect, cellular proliferation, and the expression of the pro-inflammatory (IL-6 and TNF-α) and anti-inflammatory (IL-10) cytokines were quantified in a murine model of macrophages. Results showed a potent antimicrobial activity of the Ch/AuNRs with MICs ≤4 μg/mL, very low cytotoxicity with cell viability above 80%, and the macrophage proliferation was not affected for a period of 48 h. These results suggest that our Ch/AuNR-embedded hydrogel could be an option to locally control chronic nosocomial infections using PPTT.