Risk factors for a Clostridium difficile colonization in humans

Abstract

Clostridium difficile infection (CDI) can occur in a large number of animal species and in humans. An increase in incidence and severity of CDI in humans is reported since the beginning of this century. Symptomless colonization with the bacterium has been described in many animal species, including production animals. This could lead to an increased risk of infection of humans through direct contact with these animals or through indirect contact via the environment. Consumption of contaminated food products could also increase the risk of infection. The finding of overlapping C. difficile ribotypes in humans, animals and food products has led to the hypothesis that transmission of C. difficile via animals to humans contributes to the increasing number of patients with CDI. This study tries to determine the risk factors that lead to a colonization of C. difficile in humans working with pigs or live at a pig farm. To analyze the data a multivariate logistic regression model is used. The software program for the multivariate logistic regression model is SAS 9.2 (SAS institute Inc., Cary, North Carolina, USA). No significant correlation is found between the risk factors and colonization of C. difficile in human using the multivariate logistic regression model with backward elimination. An univariate model is used to select variables for the multivariate logistic regression model. In the univariate model two significant risk factors are determined. One risk factor is a high contact frequency between persons and pigs (p=0.03). The other risk factor is administration of antibiotics to the pigs (p=0.06).