The Hazards of Probiotics on Gut-Derived Sepsis in Mice Undergoing Chemotherapy.

() is a leading cause of nosocomial infections associated with a high mortality rate and represents a serious threat to human health and the increasing frequency of antimicrobial resistance. Cancer patients are more vulnerable to invasive infection due to ulcerative lesions in mucosal surfaces and immune suppression secondary to chemotherapy. In our in vitro study, we observed that probiotics have the potential to yield beneficial effects on intestinal epithelial cells infected with . Additionally, probiotics were found to confer advantageous effects on the innate immunity of mice suffering from -induced colitis. As a result, we sought to investigate the impact of probiotics on gut-derived sepsis induced by chemotherapy. Following chemotherapy, gut-derived sepsis was induced in female C57BL/6 mice aged 6-8 weeks, which were raised under specific-pathogen-free (SPF) conditions in an animal center. Prior to the induction of the sepsis model, the mice were administered 1 × 10 colony-forming units (CFU) of the probiotics, namely (LGG) and (BL) via oral gavage. We observed that LGG or BL amplified the inflammatory mRNA expression in mice undergoing chemotherapy and suffering from gut-derived sepsis. This led to a heightened severity of colitis, as indicated by histological examination. Meanwhile, there was a notable decrease in the expression of antimicrobial peptide mRNA along with reduced levels of zonulin and claudin-2 protein staining within mucosal tissue. These alterations facilitated the translocation of bacteria to the liver, spleen, and bloodstream. To our astonishment, the introduction of probiotics exacerbated gut-derived sepsis in mice undergoing chemotherapy. Conclusively, we must be prudent when using probiotics in mice receiving chemotherapy complicated with gut-derived sepsis.