In the Endemic Setting, Clostridium difficile Ribotype 027 Is Virulent But Not Hypervirulent

Conflicting reports have been published on the association between Clostridium difficile ribotypes and severe disease outcomes in patients with C. difficile infection (CDI); several so-called hypervirulent ribotypes have been described. We performed a multicenter study to assess severe disease presentation and severe outcomes among CDI patients infected with different ribotypes.

Stool samples that tested positive for C. difficile toxin were collected and cultured from patients who presented to any of 7 different hospitals in Houston, Texas (2011-2013). C. difficile was characterized using a fluorescent PCR ribotyping method. Medical records were reviewed to determine clinical characteristics and ribotype association with severe CDI presentation (ie, leukocytosis and/or hypoalbuminemia) and severe CDI outcomes (ie, ICU admission, ileus, toxic megacolon, colectomy, and/or in-hospital death).

Our study included 715 patients aged 61±18 years (female: 63%; median Charlson comorbidity index: 2.5±2.4; hospital-onset CDI: 45%; severe CDI: 36.7%; severe CDI outcomes: 12.3%). The most common ribotypes were 027, 014-020, FP311, 002, 078-126, and 001. Ribotype 027 was a significant independent predictor of severe disease (adjusted odds ratio [aOR], 2.24; 95% confidence interval [CI], 1.53-3.29; P<.001) and severe CDI outcomes (aOR, 1.71; 95% CI, 1.02-2.85; P=.041) compared with all other ribotypes in aggregate. However, in an analysis using all common ribotypes as individual variables, ribotype 027 was not associated with severe CDI outcomes more often than other ribotypes.

Ribotype 027 showed virulence equal to that of other ribotypes identified in this endemic setting. Clinical severity markers of CDI may be more predictive of severe CDI outcomes than a particular ribotype.