First isolation of Clostridioides difficile from smoked and dried freshwater fish in Cambodia

Abstract

In Cambodia, freshwater aquaculture is the most important source of food production. Fresh fish meat is considered a highly perishable food that requires the use of different manipulations and preservation techniques to inhibit the proliferation of undesirable bacteria. These bacteria are naturally present in the raw product or could be acquired during manipulation by cross-contamination. Many studies worldwide have investigated the epidemiology of Clostridioides difficile (C. difficile) in food, but to date, there are no publications about the bacterium in ready-to-eat fish or descriptions in Cambodia. The objective of this study was to assess the presence of C. difficile in one of the main food supplies of this country, smoked freshwater fish, originating from different provinces. A total of 25 samples were collected directly from local markets, yielding 4 C. difficile isolates and an overall recovery rate of 16%. Most of the isolates were toxigenic and classified as rare PCR profiles, and they were resistant to clindamycin. These findings indicate contamination during handling and/or contamination of the raw fish, followed by insufficient heat treatment to kill the spores. The presence of C. difficile in smoked and dried fish implies a potential risk of human exposure, contamination and infection.