Hospital Roommates and the Development of Nosocomial Clostridium difficile Infection

Background: Clostridium difficile (C Difficile) is a major cause of nosocomial diarrhea in the United States. Previous studies of nosocomial C difficile infection (CDI) have documented the potential for person-to-person transmission, particularly in outbreak settings. Persistent environmental contamination and carrying of the organism on the hands of hospital staff are common. Interestingly, C difficile types are commonly found to be highly diverse, and isolates from epidemiologically linked patients infrequently represent the same strain. The role of co-occupancy with and time of exposure to individuals with CDI have not been very well studied as independent risk factors for development of symptomatic nosocomial CDI.

Objective: To determine whether room co-occupancy and time of exposure to individuals with C difficile are risk factors for development of nosocomial CDI.

Methods: We conducted a retrospective cohort study. A total of 120 inpatients ages 18 and older who shared a room with an index case between April 2008 and June 2009 were identified using data from our quality department. An unexposed control group of 125 patients matched for patient unit, length of stay, race and time frame was generated. Intensive care unit patients were excluded from the study. Charts were reviewed focusing on the outcomes of interest. Development of CDI was followed from the beginning of exposure until one month after discharge. Univariate and multivariate analysis were conducted.

Results: There was no statistically significant difference in the rate of development of CDI on those patients exposed to an index case compared to those not exposed (7.5% and 3.2%). Time of exposure was significantly longer in those who developed CDI (4.6 days vs 2.1 days, p=0.034). For every one-day increase in time of exposure, the likelihood of developing CDI increased significantly (OR 1.19, CI 1.02 – 1.4). Patients who developed CDI were more likely to have received antibiotics, have inflammatory bowel disease (IBD), liver disease, and have a longer length of stay (p<0.05). On multivariate analysis, IBD and length of stay were independent risk factors. Use of proton pump inhibitors was not significantly different in both groups.

Conclusions: There was a trend towards a higher rate of development of CDI in those patients exposed to an index case. Time of exposure was an independent risk factor for development of CDI based on multivariate analysis. Use of antibiotics, length of stay, IBD and liver disease were also found to be associated with development of CDI, with length of stay and IBD being independent risk factors. Use of proton pump inhibitors was not associated with development of CDI in our study.