Bacterial resistance to antibiotics is a significant threat to global health, and innovative strategies are needed to tackle these bacterial infections. In this study, we used an in vitro bactericidal assay to demonstrate that small silver nanoclusters (AgNCs) coated with 5-mercapto-2-nitrobenzoic acid (MNBA) exhibit bactericidal activity against a range of Gram-negative and Gram-positive ESKAPEE bacteria and bacteria belonging to the WHO Priority Pathogen List. Understanding the broad-spectrum antibacterial properties of MNBA-AgNCs highlights the importance of nanoparticle customization in further combating antimicrobial resistance.