In a retrospective cohort study conducted in a medical intensive care unit (ICU) at a tertiary-care hospital, Megan K. Shaughnessy MD, of the Department of Internal Medicine at the University of Michigan Health System, and colleagues evaluated whether admission to a room previously occupied by a patient with C. difficile infection (CDI) increased the risk of acquiring CDI. Their research was published in Infection Control and Hospital Epidemiology.
Among 1,844 patients admitted to the ICU, the researchers say they identified 134 CDI cases; after exclusions, 1,770 admitted patients remained for analysis. Of the patients who acquired CDI after admission to the ICU, 4.6 percent had a prior occupant without CDI, while 11 percent had a prior occupant with CDI. The researchers report that the CDI status of a prior room occupant in this study was a statistically significant risk factor for acquisition of CDI in the medical ICU, independent of such known CDI risk factors as greater age, greater severity of illness, and proton pump inhibitor and antibiotic use. They say their findings underscore the importance of the hospital environment in transmission of serious infections and the need for improved hospital design that incorporates single-patient rooms and bathrooms.
Of note, Shaughnessy, et al. emphasize that their study "potentially raises questions regarding the importance of diligent isolation practices and proper environmental cleaning." The researchers add, "Disinfection with a 1:10 dilution of bleach has been effective in reducing the frequency of environmental contamination with C. difficile. This, combined with handwashing with soap and water, contact precautions, and isolation of patients, can limit the spread of CDI. In an effort to decrease CDI transmission, starting in April 2007 the policies at the study institution changed to include cleaning every patient room with bleach after discharge regardless of the patients CDI status. Contact precautions were also initiated for all patients with CDI. Future directions of our investigations include reevaluating the effect of a prior room occupants CDI status with the new cleaning and isolation methods in place. The effect of other room decontamination options could also be explored, such as the use of hydrogen peroxide vapor, which has been shown to reduce the incidence of nosocomial CDI. Other future directions include evaluating whether asymptomatic colonized patients contribute to increased risk to the next room occupant and determining the relationship between the duration of spores in the environment and the likelihood that they could cause disease."
Reference: Shaughnessy MK, Micielli RL, DePestel DD, Arndt J, Strachan CL, Welch KB and Chenoweth CE. Evaluation of Hospital Room Assignment and Acquisition of Clostridium difficile Infection. Infect Control Hosp Epidem. Vol. 32, No. 3. March 2011.