For the first time, this study was carried out to investigate and evaluate the relative antibacterial activity of three different Nk-lysin peptides from human, chicken, and bovine activity compared to Gram-negative and Gram-positive bacteria as well as antiviral activity against rotavirus (strain SA-11) and finally mechanisms of action optionality. This report is the first of its kind that investigates the increased antimicrobial ability of (Nk-lysin + AgNPs) and (Nk-lysin + human IL-2) combinations against S. typhi activity by carrying out direct comparison under similar experimental settings. Our results showed that gram-negative and gram-positive microorganisms, including Streptococcus pyogenes, Streptococcus mutans, Escherichia coli, Pseudomonas aeruginosa, Klebsiella oxytoca, Shigella sonnei, Klebsiella pneumoniae and Salmonella typhimurium, are susceptible to NK-lysin treatment. It was shown in our findings that there was equal potentiality in mixture (Nk-lysin + AgNPs) and (Nk-lysin + human IL-2) for preventing the growth of S. typhi, however, when added together, there was minor increase in the level of action. In our study, the TOHO-1 gene was absent in treated bacteria. Following treatment with Nk-lysin peptides, the beta-lactamases genes (CTX-M-1, M-8, and M-9) were not found in any bacterial strains. The examination did not find any of the plasmid mediated quinolone resistance genes in the bacterial strains as a response to NK-lysin treatment. Nonetheless, no study has been carried out in the past that characterized the antiviral activity of bovine, human and chicken Nk-lysin peptides. Hence, this is the foremost study on the enhanced antimicrobial activity of human, bovine and chicken Nk-lysin peptides against Rotavirus (strain SA-11). The findings of the study demonstrated that the powerful antiviral activities were exhibited by Nk-lysin peptides against Rotavirus (strain SA-11). Based on the comparison between these peptides, it can be concluded that there is an evident potent antiviral activity of bovine Nk-lysin against Rotavirus (strain SA-11) as it restrains infection by up to 90%. However, growth was restricted by 80% by chicken Nk-lysin and by 50% by the human peptide.