Ribotype variability of Clostridioides difficile strains in patients with hospital-acquired C. difficile infections, community-acquired C. difficile infections, and colonization with toxigenic and non-toxigenic strains of C. difficile.

There have been few available data that presented a direct comparison between polymerase chain reaction ribotype (RT) distribution of Clostridioides difficile strains from C. difficile infection (CDI) and colonization. To understand the epidemiology of CDI in a hospital setting, we compared RTs of C. difficile strains from hospital-acquired CDI (HA-CDI) and toxigenic colonization and from community-acquired CDI (CA-CDI) and non-toxigenic colonization using the stool samples submitted for C. difficile cultures at an institution during 2009, 2012, and 2014. Overall, 721 C. difficile strains were identified from 607 patients. Among them, 450 (62.4%) were HA-CDI, 20 (2.8%) were CA-CDI, 126 (17.5%) were toxigenic colonization, and 125 (17.3%) were non-toxigenic colonization. RT018, RT017, RT002, RT015, and RT001 isolates were the most prevalent RTs in HA-CDI, and they comprised 74.9% of the total HA-CDI isolates but accounted for 60.4% of isolates from toxigenic colonization. In total, 32 strain compromising 18 RTs from HA-CDI (7.1%) were not seen among the toxigenic colonization group, and 3 RTs with 5 strains from toxigenic colonization were not seen among the HA-CDI group. The distribution of RTs was the most diverse in CA-CDI and the least diverse in HA-CDI. Although 5 RT strains, which were prevalent in HA-CDI, comprised 40% of CA-CDI, 5 isolates (25%) revealed unknown RTs, which were uncommon in HA-CDI or toxigenic colonization. In 12 patients with both episodes of CDI and toxigenic colonization, 8 had 2 isolates with different RTs and 4 had isolates with identical RTs. In conclusion, although RT017 and RT018 were the most common in HA-CDI and toxigenic colonization, C. difficile strains from toxigenic colonization were more diverse than those from HA-CDI.