Additive activity of the two AMPs HNP 1-3 and LL-37 in a colony forming unit (CFU) assay against N . farcinica ATCC 3318. A combination of HNP 1-3 and LL-37 exhibited killing comparable to each peptide alone at twofold higher concentrations (i.e. 78.9% CFU reduction by 8 μg/ml HNP 1-3 in combination with 8 μg/ml LL-37 compared to 68.5% CFU reduction by 16 μg/ml LL-37 or 45.6% reduction by 16 μg/ml HNP 1-3 alone). Data are results of a single assay.