oa Exploring the Role of Cathelicidin Antimicrobial Peptide, Toll-Like Receptor 4, and HMGB-1 in Bacterial Infection

Background and Aim: Lipopolysaccharides (LPS) from Salmonella typhi will attach with Toll-Like Receptor 4 (TLR-4) and trigger an inflammatory response to fight the pathogen. Due to infection, the HMGB1 is produced by immune cells or secreted passively from dead cells. Furthermore, the antimicrobial peptide, cathelicidin was secreted to neutralize and eliminate these pathogens. This study aims to examine the interaction of Cathelicidin antimicrobial peptide (CAMP), TLR-4, and HMGB-1 on inhibiting bacterial growth in Salmonella infection. Methods: This study is an experiment that uses a pre-post-test design. Mice balb/c were separated into three groups; group A received levofloxacin for five days, group B received a placebo, and group C was the control. Both groups, A and B, received an injection of S. Typhi strain thy1. Blood samples were taken from three groups on the 4th, 10th, and 30th day to calculate CAMP, TLR-4, and HMGB-1 mRNA gene expression levels. To determine bacterial colony, peritoneal fluid was taken three times on the 4th, 10th, and 30th day to calculate bacterial colony. Results: Our finding observed that the expression of mRNA CAMP was inversely related to bacterial colony count, which means that higher CAMP mRNA expression was associated with reduced bacterial colony count in groups A and B. The expression of HMGB-1 mRNA was found to be positively correlated with bacterial growth in group A. Meanwhile, TLR-4 mRNA expression did not significantly correlate with bacterial colony count in any groups. Conclusions: CAMP, TLR-4, and HMGB-1 affect bacterial infections. Higher expression CAMP mRNA levels lower colony counts. Meanwhile, decreasing TLR-4 and HMGB-1 mRNA expression were found during the study, due to reducing growth bacteria.