Clostridioides difficile positivity rate and PCR ribotype distribution on retail potatoes in 12 European countries, January to June 2018.

BackgroundWhile human-to-human transmission of Clostridioides difficile occurs often, other infection sources, including food, animals and environment, are under investigation.AimWe present a large study on C. difficile in a food item in Europe, encompassing 12 European countries (Austria, France, Greece, Ireland, Italy, the Netherlands, Poland, Slovakia, Spain, Sweden, Romania and the United Kingdom).MethodsPotato was selected because of availability, ease of sampling and high C. difficile positivity rates. Identical protocols for sampling and isolation were used, enabling a direct comparison of the C. difficile positivity rate.ResultsFrom C. difficile-positive potato samples (33/147; 22.4%), we obtained 504 isolates, grouped into 38 PCR ribotypes. Positivity rates per country varied (0-100%) and were at least 10% in 9/12 countries. No geographical clustering of samples with high positivity rates or in PCR ribotype distribution was observed. The most frequently detected PCR ribotypes (014/020, 078/126, 010 and 023) are also commonly reported in Europe among human clinically relevant isolates, in animal isolates and in the environment. Whole genome sequencing revealed several genetically related strain pairs (Spain/RT126, France/RT010, Austria and Sweden/RT276) and a cluster of very similar strains in RT078/126.ConclusionOur results suggest, the high potato contamination rates could have public health relevance. They indicate potatoes can serve as a vector for introducing C. difficile spores in the household environment, where the bacterium can then multiply in sensitive hosts with disrupted or unmature microbiota. Potato contamination with PCR ribotypes shared between humans, animals and soil is supportive of this view.

High Clostridium difficile contamination rates of domestic and imported potatoes compared to some other vegetables in Slovenia.

Clostridium difficile, recently reclassified to Clostridioides difficile, is among most important causes of intestinal infections in humans. Zoonotic potential and foodborne transmissions are considered to be partially involved in C. difficile spread. Here we report prevalence of C. difficile in 142 retail and 12 homegrown vegetables in Slovenia between years 2014 and 2017. The overall prevalence of C. difficile on vegetables was 18,2% (28/154). A total of 115 isolates were obtained which belonged to 25 PCR ribotypes. Ten of those were toxigenic and PCR ribotype 014/020 was the most prevalent. Most of 25 determined PCR ribotypes were previously reported in humans, animals, soil or water in Slovenia. Among tested vegetables, potatoes had the highest positivity rate (28,0% vs. 6,7% and 9,4% for ginger and leaf vegetables). Altogether 66,7% of C. difficile positive potato samples were imported from 12 different countries of three different continents. The origin of contamination could be any point between production and retail store, however, our results suggest a possibility that potatoes represent a transnational and transcontinental way of C. difficile transmissions.