The lasso peptide produced by Bacillus licheniformis MCC 2514 demonstrates efficacy in treating in-vivo Salmonella Typhimurium infection

Salmonella, a significant pathogen transmitted through food, presents a substantial threat to public health. The
issue of antibiotic misuse is causing a quest for alternative replacements. An antimicrobial peptide, predicted as
lasso peptide 2514 (LP-2514), derived from the probiotic bacteria Bacillus licheniformis MCC 2514, has demon-
strated effectiveness against various foodborne pathogens including Salmonella. This study aims to assess the
efficacy of this peptide in vivo. Mice infected with Salmonella Typhimurium received daily oral administration of
LP-2514 (30 mg/kg/day) for 2 weeks until the symptoms subsided. After the treatment, biochemical and his-
topathological parameters were examined. LP-2514 treated mice demonstrated reduced infection, as evidenced
by a 5-fold decrease in aspartate aminotransferase concentration and a 10-fold decrease in alanine amino-
transferase concentration in plasma. Nitric oxide generation was decreased by 61.23 %, C-reactive protein by
75.9 %, and numerous antioxidant enzymes were elevated to suppress the infection. Increased expression of the
anti-inflammatory marker Interleukin-10 (IL-10) by 43-fold was observed in treated mice, while untreated mice
displayed elevated expression of pro-inflammatory cytokines indicating the severity of infection. Hence, LP-2514
successfully alleviated the disease symptoms caused by S. Typhimurium, thus exhibiting as a potential replace-
ment for antibiotics or food-grade preservatives.