Development of a Standardized Scoring System to Assess a Murine Model of Clostridium difficile Colitis

Abstract

Background: Clostridium difficile infection is the most common cause of antimicrobial-associated diarrhea. Our aim was to introduce a novel and efficient clinical sickness score (CSS), and to define a detailed histologic injury score (HIS) in a murine model of C. difficile colitis. Methods: Mice received an antibiotic cocktail (kanamycin, gentamicin, colistin, metronidazole, and vancomycin) for 96 h. After 48 h, mice received an intraperitoneal injection of clindamycin, followed by oral C. difficile (1.5 × 10⁷ CFU). Signs of sickness were scored using a novel CSS (range 0–12) with scores ≥6 consistent with C. difficile colitis. Intestinal tissue was analyzed utilizing an adapted HIS (range 0–9) with scores ≥4 consistent with C. difficile colitis. Stool was analyzed for C. difficile, and survival evaluated. Results: No control mice showed signs of sickness, whereas 23% of mice receiving antibiotics alone and 65% of mice exposed to antibiotics and subsequently C. difficile demonstrated signs of sickness (p = 0.0134). No control mice had histologic injury, whereas 8% of mice receiving antibiotics alone and 75% of mice exposed to antibiotics followed by C. difficile had evidence of histologic injury (p = 0.0001). Mice exposed to C. difficile lost more weight, although not significant (p = 0.070). Mice that received C. difficile had decreased survival compared to control mice and mice receiving antibiotics only (p = 0.03). Conclusions: We have developed a novel clinical scoring system, and detailed histological grading system, that enables the objective evaluation of a murine C. difficile colitis model. This model allows the study of this disease in a host that demonstrates clinical and histologic signs comparable to human C. difficile infection. This will allow for improved study of therapeutics for this disease in the future.

Keywords:

• C. difficile
• colitis
• model
• mouse
• scoring system

Acknowledgments

We thank Yijie Wang (Nationwide Children’s Hospital, Laboratory of Dr. Gail Besner) who played an integral role in experiment concept and design, obtaining all necessary supplies, animals, and overall function of the experiments. We thank Ann Salvator (Nationwide Children’s Hospital, Biostatistics Core) who assisted with the data analysis.

Declaration of interest

The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.