Prevalence and molecular types of Clostridioides (Clostridium) difficile on Australian retail vegetables and...

Community-onset Clostridioides (Clostridium) difficile infection (CDI) has risen to >80 % of all CDI cases in Australia. High prevalence of C. difficile contamination has been reported in many community sources including retail root vegetables. Household surfaces may become contaminated with C. difficile when storing and handling contaminated vegetables. This study aimed to determine the prevalence and molecular types of C. difficile present on retail root vegetables and household surfaces.

From April 2023 to March 2024, retail potatoes (n = 255) and onions (n = 305) were sampled at 3-monthly intervals. Environmental samples were collected from homes of householders in Queensland (n = 105) and Western Australia (n = 124) who regularly purchased unwashed potatoes. Swabs were collected from their countertop/chopping board, vegetable storage area and an unwashed potato. Pooled potato peels, pooled onion roots and household swab samples underwent enrichment culture for C. difficile. C. difficile isolates were characterized by PCR ribotyping and detection of toxin genes.

C. difficile was cultured from 5.6 % of all 679 household samples, 35.3 % of 255 retail potato samples and 20.3 % of retail onion 305 samples. At least one environmental/potato sample was positive for 15.7 % of all 229 households. Among 84 C. difficile ribotypes (RTs), 056, 286, 101 and 125 predominated on vegetables in Western Australia and RTs 101, QX 098, 014/020 and QX 601 were most common on Queensland vegetables.

Toxigenic strains of C. difficile were identified on retail vegetables and within households, highlighting potential for CDI to be acquired within households. Populations at high risk of CDI e.g. patients with inflammatory bowel disease or cancer, could benefit from education on safe handling and cleaning of potential sources of C. difficile in their homes.