-Review-

Diagnosis and Treatment of Clostridioides difficile Infection

Jun Hirai

Division of Infection Control and Prevention, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan

Clostridioides difficile infection (CDI) remains a leading cause of healthcare-associated diarrhea worldwide, with high morbidity, recurrence, and healthcare burden. Timely and accurate diagnosis, effective treatment, and preventive strategies are critical in improving patient outcomes. This review presents a comprehensive overview of CDI and focuses on diagnostic criteria, severity classifications, recurrence risk prediction, and therapeutic approaches, emphasizing both international and Japanese perspectives. The use of the Bristol Stool Scale and appropriate stool testing protocols helps ensure diagnostic accuracy and avoid overtreatment. Japan's adoption of the MN severity criteria, which incorporate clinical, laboratory, and imaging findings, contrasts with laboratory-based classifications in international guidelines. While both structured diagnostic algorithms and evidence-based treatment guidelines offer prognostic value, MN criteria may better reflect real-world clinical decision-making in Japan. CDI recurrence remains a significant clinical challenge. This review highlights two predictive models-CHIEF score and the novel Days of Antibiotic Spectrum Coverage (DASC) metric-developed in Japanese cohorts. Both tools enable early identification of high-risk patients and support decisions on prophylactic or tailored therapy. Therapeutic options include fidaxomicin (FDX), vancomycin, and metronidazole (MTZ). Recent international guidelines favor FDX due to its superior microbiota-sparing properties and reduced recurrence rates. However, MTZ remains an option for mild cases in Japan because of cost considerations and differences in CDI strain prevalence. By comparing local and global practices, this review underscores the importance of region-specific data in optimizing CDI management and encourages further integration of emerging risk stratification tools and treatment strategies to improve care across diverse clinical settings.

J Nippon Med Sch 2026; 93: 1-11

Keywords
Clostridioides difficile, Bristol Stool Scale, recurrent risk, MN criteria, fidaxomicin

Correspondence to
Jun Hirai
j-hirai@nms.ac.jp

Received, April 28, 2025
Accepted, June 30, 2025