SMAP-18, an 18-amino acid residue peptide amide, is a biologically active truncated variant of Sheep myeloid antimicrobial peptide-29 (SMAP-29). It retains potent antimicrobial activity against Pseudomonas strains, other Gram-negative bacteria, and multidrug-resistant pathogens. Notably, SMAP-18 exhibits increased cell selectivity relative to the parent peptide SMAP-29 due to its reduced hemolytic activity while maintaining its antimicrobial efficacy.