Seasonality ofClostridium difficilein the natural environment

Abstract

Clostridium difficile is considered the leading cause of antibiotic‐associated disease worldwide. In the past decade, a large number of studies have focused on identifying the main sources of contamination in order to elucidate the complete life cycle of the infection. Hospitals, animals and retail foods have been considered as potential vectors. However, the prevalence of C. difficile in these types of samples was found to be rather low, suggesting that other contamination routes must exist. This study explores the presence of C. difficile in the natural environment and the seasonal dynamics of the bacterium. C. difficile was isolated from a total of 45 samples out of 112 collected (40.2%) on 56 sampling points. A total of 17 points were positive only during the winter sampling (30.4%), 10 were positive only during the summer sampling (17.9%) and 9 sampling points (16.1%) were positive in both summer sampling and winter sampling. Spore counts in soil samples ranged between 50 and 250 cfu/g for 24.4% of the positive samples, with the highest concentrations detected in samples collected in the forest during winter campaign (200–250 cfu/g). A total of 17 different PCR ribotypes were identified, and 15 of them had the genes coding for toxins A and B. Most of those ribotypes had not previously been found or had been isolated only sporadically (<1% of samples) from hospitals in Belgium. Regarding antimicrobial susceptibility, most of the resistant strains were found during the summer campaign. These findings bear out that C. difficile is present in the natural environment, where the bacterium undergoes seasonal variations.

High Prevalence of Clostridium difficile in Home Gardens in Western Australia

“…Of the 87 isolates of C. difficile, 33 (38%; CI 28-48%) were toxigenic, comprising A+B+CDT+ (n=1), A+B+CDT-(n=27), A-B-CDT+ (n=1) and A+B-CDT-(n=4), and 54 (62%; CI 52-72%) were non-toxigenic (A-B-CDT-). Of note, 37% (CI 24-50%) of the soil isolates harboured toxigenic C. difficile strains, comparable to soil studies elsewhere (44% in Slovenia, 73% in Belgium, 67% and 99.5% in Zimbabwe) (21,29,31,33).…”

“…While home gardens do not appear to have been studied previously in Australia, studies of homes per se recovered C. difficile from 31-38% of sites, predominantly household domestic items, pets, various surfaces, dust from vacuum cleaners, bathrooms and toilets, and shoe soles (14,27,28). The overall prevalence of C. difficile in our garden samples was higher than other contemporaneous reports (6.5-48%) on environmental samples (21,26,(29)(30)(31). The extent of contamination in home gardens in Perth on December 1, 2020 at UNIV OF WESTERN AUSTRALIA M209 http://aem.asm.org/ Downloaded from is likely to be due to the practice of adding compost and manure to the poor-quality soils in WA.…”

“…Studies on environmental contamination with C. difficile have shown a number of potential sources including soil (7,8), water (9, 10), animals (11)(12)(13), households (14) and food (15)(16)(17)(18)(19)(20), in addition to patients colonized with C. difficile (21), with cases acquiring infection through the oro-faecal route with ingestion of spores. This has been suspected due to the on December 1, 2020 at UNIV OF WESTERN AUSTRALIA M209 http://aem.asm.org/ Downloaded from overlapping of ribotypes (RTs) of C. difficile found in the environment, animals and humans (22,23).…”

High contamination rates of shoes of veterinarians, veterinary support staff and veterinary students with Clostridioides difficile spores

“…Our isolates belonged to ribotypes well known from human, animal and environmental studies (Davies et al, 2016;Janezic et al, 2016;Rodriguez et al, 2019;Silva et al, 2015).…”

“…Dogs' paws were described as a possible source of C. difficile spores in households (Janezic et al., 2018 ). Moreover, dog's nasal discharge has been lately reported as a possible new source of C. difficile transmission (Rodriguez et al., 2019 ).…”