An outbreak of Clostridium difficile infections due to new PCR ribotype 826: epidemiologic and microbiologic analyses

Abstract Objectives To investigate an unusual outbreak of five patients with a total of eight episodes of a Clostridium difficile infection on a gastrointestinal surgical ward of a Dutch tertiary-care, university-affiliated hospital. Methods Clinical case investigations and laboratory analyses were performed. Laboratory analyses included PCR ribotyping, multiple-locus variable-number tandem repeat analysis typing, toxin typing, antimicrobial susceptibility testing and whole genome sequencing. Results The outbreak was associated with recurrent and severe disease in two of five patients. All episodes were due to a unique ribotype that was not recognized in the collection of an international network of reference laboratories and was assigned PCR ribotype 826. PCR ribotype 826 is a toxin A–, toxin B– and binary toxin–positive ribotype which according to molecular typing belongs to clade 5 and resembles the so-called hypervirulent ribotype 078. The presence of a clonal outbreak was confirmed by whole genome sequencing, yet the source of this newly identified ribotype remained unclear. Conclusions This newly identified C. difficile PCR ribotype 826 is part of clade 5 and might also have increased virulence. The recognition of this outbreak highlights the need for ongoing C. difficile infection surveillance to monitor new circulating ribotypes with assumed increased virulence.