Comparison of Clostridium difficile isolates from individuals with recurrent and single episode of infection.

PURPOSE: Recurrent Clostridium difficile infection (CDI) is an increasing problem, yet reasons for this are poorly understood. Attention has been paid to the role of strain, with conflicting association of ribotype 027 and recurrences.

METHODS

Stool samples and medical records data were collected from 60 patients: 27 with recurrent CDI and 33 with single episode CDI. C. difficile was isolated and ribotyped, and minimum inhibitory concentrations of metronidazole and vancomycin were determined by Etest.

RESULTS

Twenty-seven ribotypes were identified, but only four (027, 014 and two internally designated strains) were found in more than one patient. Ribotype 027 predominated and was significantly over-represented in the recurrent CDI group (70%) versus the single episode CDI group (30%) (P = 0.004). Female gender and the presence of ribotype 027 were significantly associated with recurrent CDI in the multivariable model. Metronidazole MICs for recurrent isolates were significantly higher compared to single episode isolates (P ≤ 0.024). A general linear model indicated that the difference in MIC was associated with ribotype 027 (P = 0.0023), not whether the isolate was from recurrent or single episode disease (P = 0.25).

CONCLUSIONS

Ribotype 027 was associated with recurrent disease. While there was no difference in the prevalence of metronidazole resistance, isolates from recurrent CDI patients had significantly higher metronidazole MICs, because of higher MICs in ribotype 027. This study provides further support to the clinical importance of ribotype 027 and raises questions about the potential impact of decreased metronidazole susceptibility on the pathophysiology of recurrent CDI.