Clinical characteristics of relapses and re-infections in Clostridium difficile infection

The purpose of this study was to identify factors associated with relapses or re-infections in patients with recurring Clostridium difficile infections (CDIs). From September 2008 to January 2012, cases with two or more isolates from consecutive CDI episodes were included. PCR-ribotyping and multilocus variable-number tandem-repeat analysis were performed using paired isolates. Among 473 patients, 68 (14.4%) experienced one to five recurrences. Fifty-one of these with two or more isolates from consecutive CDI episodes were included in the study; 25 (49%) were classified as relapses and 26 (51%) as re-infections. Recurrence interval was shorter in the relapse group (26.0 versus 67.5 p 0.001), but more patients in the re-infection group were hospitalized during recurrence interval (53.8% versus 8.0%, p <0.001). Relapse rates in infections by ribotype 017, ribotype 018 and other ribotypes were 63.6%, 63.6% and 22.2%, respectively (p 0.274, p 0.069, and p 0.005). In multivariate logistic regression, infections by ribotypes 017 and 018 were associated with CDI relapse (OR 4.77, 95% CI 1.02-22.31, p 0.047; OR 11.49, 95% CI 2.07-63.72, p 0.005). Conversely, admission during recurrence interval lowered the risk of relapse (OR 0.044, 95% CI 0.006-0.344, p 0.003). In conclusion, relapse was more likely when infection was caused by PCR ribotypes 017 and 018.