All cyclic peptides displayed antibacterial activity against S. aureus, E. faecium, B. subtilis, and B. cereus, with minimum inhibitory concentrations (MICs) in the range of 1.5-6.2 µg/mL. Notably, most of the cyclic peptides showed similar activities against the antibioticresistant strains of S. aureus and E. faecium. Compared to E. faecium, most of the cyclic peptides showed slightly reduced activity against both wild type (MIC = 3.1-12.5 µg/mL) and vancomycin-resistant (MIC = 6.2-12.5 µg/mL) E. faecalis. Interestingly, while all cyclic peptides displayed moderate activity against wild-type S. pneumoniae (MIC = 25-50 µg/mL), most of the cyclic peptides showed 1 to 2-fold higher activity against antibiotic-resistant S. pneumoniae (MIC = 12.5-25 µg/mL). Compared to standard antibiotic daptomycin, most of the cyclic peptides showed comparable or higher activity against vancomycin-resistant strains of E. faecium and E. faecalis (Table , Supporting Information).