Clinical outcomes of Clostridium difficile infection according to strain type. A prospective study in medical wards.

Objectives: To describe clinical characteristics and outcome of Clostridium difficile infection (CDI) patients in Internal Medicine, to identify ribotypes (RTs); to evaluate the association between RT and patient clinical characteristics and report outcome.

Methods: One year prospective cohort study. Clinical data, Barthel Index (BI) and outcomes were collected for all inpatients suffering from CDI (n = 148) in hospital wards in Northern Italy. 84 fecal samples were analysed for molecular typing.

Results: 12 RTs were identified, predominantly RT018 (42.9%, n = 36/84) and RT356/607 (40.5%, n = 34/84). Patients with dementia were more frequent among those infected by RT018 [55.6% (n = 20/36) vs. 32.4% (n = 11/34), p = 0.05]. The median BI score of patients with RT018 was lower than BI score of patients with RT356/607 [10 (IQR 0-32) vs. 15 (IQR 5-50), p = 0.06]. RT018 infection was associated to higher levels of C-reactive protein [7.2 mg/dl (IQR 4.1-14.7) vs. 4.0 mg/dl (IQR 2.2-6.8), p = 0.01] and white blood cells ≥15,000/dl [33.3% (n = 12/36) vs. 14.7% (n = 5/34) of patients, p = 0.07]. Higher mortality was noted among RT018 infected patients. We found a continuous mortality increase according to the ATLAS score.

Conclusions: Our results confirm that RT018 and RT356/607 are the two major RTs causing CDI in older patients with a high degree of disability in Northern Italy and RT018 is associated with more serious outcomes.