Highly Divergent <i>Clostridium difficile</i> Strains Isolated from the Environment

<div><p><i>Clostridium difficile</i> is one of the most important human and animal pathogens. However, the bacterium is ubiquitous and can be isolated from various sources. Here we report the prevalence and characterization of <i>C</i>. <i>difficile</i> in less studied environmental samples, puddle water (n = 104) and soil (n = 79). <i>C</i>. <i>difficile</i> was detected in 14.4% of puddle water and in 36.7% of soil samples. Environmental strains displayed antimicrobial resistance patterns comparable to already published data of human and animal isolates. A total of 480 isolates were grouped into 34 different PCR ribotypes. More than half of these (52.9%; 18 of 34) were already described in humans or animals. However, 14 PCR ribotypes were new in our PCR ribotype library and all but one were non-toxigenic. The multilocus sequence analysis of these new PCR ribotypes revealed that non-toxigenic environmental isolates are phylogenetically distinct and belong to three highly divergent clades, two of which have not been described before. Our data suggest that environment is a potential reservoir of genetically diverse population of <i>C</i>. <i>difficile</i>.</p>