Serum bacterial toxins are related to the progression of inflammatory bowel disease

Abstract

Objectives. Inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), is an autoimmune disease. Disorder of intestinal microbes is thought to play a critical role in the pathogenesis of IBD. Detection of bacterial toxins could become a new approach to judge the situation of this disease. Materials and methods. Serum samples were collected from 142 IBD patients and 40 healthy donors as well as 15 CD patients with anti-tumor necrosis factor (TNF) monoclonal antibody (infliximab [IFX]). Enzyme-linked immunosorbent assay kits for Clostridium difficile, Escherichia coli O157, salmonella, and Staphylococcus aureus were used to analyze these bacterial toxins in sera. Results. The positive rates of bacterial toxins from C. difficile, E. coli O157, salmonella, and S. aureus in the IBD patients were found in low incidences and associated with disease duration, colonic involvement, and treatment with prednisone and immunomodulators. The active CD and UC patients had significant higher positive rates of these bacterial toxins than those in remission or healthy controls. Blockage of TNF with IFX in CD patients resulted in significant decreases of the levels of toxins of C. difficile, E. coli O157, salmonella, and S. aureus in sera. Conclusions. Some bacterial toxins are present in the sera of active IBD patients, and patients with long disease duration, colonic involvement, or treatment with prednisone and immunomodulators are more susceptible to bacterial infection. Inhibition of inflammation with IFX would reduce the bacterial toxins via improvement of intestinal inflammation. Detecting bacteria-derived toxins in sera can be used to predict the progression of IBD.

Key Words::

• Clostridium difficile
• Escherichia coli O157
• inflammatory bowel disease
• salmonella
• Staphylococcus aureus
• toxin

Acknowledgments

This work is supported by grants from the National Natural Science Foundation of China (81270470), and Shanghai Science and Technology Commission (12XD1404000). Authors’ contributions: Huajing Qiu, Xiaomin Sun, and Mingming Sun performed all of the experimental analyses, data collection, and statistical analysis. Chong He collected data. Huajing Qiu drafted the manuscript. Zhong Li analyzed data, and prepared and critically reviewed the manuscript. Zhanju Liu designed experiments, analyzed data, and prepared the manuscript. All authors read and approved the final manuscript.

Declaration of interest: The authors alone are responsible for the content and writing of the paper.