Japanese Society for Infection Prevention and Control-Online Journal

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Epidemiological Study of Clostridioides difficile in a Hospital with the Multilocus Sequence Type 17 (ST17) Strain as the Predominant Strain

Masayuki MUKAI¹⁾, Tamako ABE²⁾, Takashi SATO²⁾, Toshiya SATO³⁾, Taichi TAKASHINA⁴⁾ and Meiji Soe AUNG⁵⁾
¹⁾Department of Pharmacy, Iwamizawa Municipal General Hospital, ²⁾Department of Infection Control Office, Iwamizawa Municipal General Hospital, ³⁾Department of Pediatrics, Iwamizawa Municipal General Hospital, ⁴⁾Department of Internal Medicine, Iwamizawa Municipal General Hospital, ⁵⁾Division of Hygiene, Department of Social Medicine, Sapporo Medical University School of Medicine

In January 2023, 15 cases of Clostridioides difficile infection (CDI) were reported in three wards of our hospital, and an outbreak was suspected based on our institutional criteria. Therefore, we retrospectively investigated CDI testing and incidence rates in each ward between January and November 2023 to confirm the outbreak. The strains isolated and cultured from inpatients and outpatients with CDI were analyzed using multilocus sequence typing (MLST). In January, the incidence rates of CDI in the three wards were 66.7, 33.8, and 76.0 per 10,000 patient-days (/10,000 PD), respectively, indicating an outbreak that resolved in the following month. However, there was an incidence rate of 81.4/10,000 PD cases in one ward in July. In the dialysis outpatient unit, there were 8 patients (13 episodes) with CDI in 2023, compared with only one patient in 2022. Of the 26 isolates from 23 patients in the three wards and the dialysis outpatient unit, 18 isolates from 15 patients (69%) were identified as sequence type 17. There was an outbreak of CDI caused by ST17 in three wards and in the dialysis outpatient unit. These findings suggest nosocomial transmission within the outpatient dialysis unit. Our current institutional criteria made determining the onset and termination of an outbreak difficult. Therefore, the criteria were revised to compare the incidence of CDI with the baseline during non-outbreak periods. This experience reaffirmed the importance of contact precautions for patients with CDI and adherence to basic infection control practices throughout the hospital, including in outpatient settings.

Key words：Clostridioides difficile, MLST, outbreak

e-mail: pharmacy＠med.hamanasu.com

Received: October 15, 2024
Accepted: March 27, 2026

41 (4)：156─164,2026