Among low-income nations, diarrhea is a major cause of illness and mortality in children. Although a variety of microorganisms can cause diarrhea, the cause of many cases was unknown. Serratia marcescens has been linked to hospital-acquired infections as well as HIV/AIDS-related diarrhea. Serratia spp. have recently been discovered to be more frequent in the stools of diarrhea patients than in asymptomatic control youngsters. Using a polarised human colonic epithelial cell (T84) monolayer, the researchers evaluated the potential intestinal pathogenicity of S. marcescens in vitro. Scanning electron microscopy was used to examine infected monolayers for bacterial invasion, transepithelial electrical resistance (TEER), cytotoxicity, interleukin-8 (IL-8) production, and morphological alterations. S. marcescens caused substantially more epithelial cell invasion than Escherichia coli strain HS (P=0.0038, respectively). The invasion of cells was followed by a decrease in TEER and IL-8 secretion. Within a few hours of being exposed to S. marcescens, the extracellular concentration of lactate dehydrogenase (LDH) increased dramatically. Microvilli destruction and vacuolization were observed using scanning electron microscopy on S. marcescens-infected monolayers. S. marcescens interact with intestinal epithelial cells in culture and causes severe changes similar to those seen in established enteric infections, according to the researcher’s findings.