Transmission of C. difficile: Asymptomatic carriers are also a risk

A new paper from Canada that has examined the effect of screening and isolation for asymptomatic carriers of toxigenic C. difficile has just been released onto the JAMA Internal Medicine website. In this study, 4.8% of patients screened were found to be carrying the tbD gene and these patients were part of an intervention group that included isolation, but not in the traditional sense as shared bays were permissible however the curtains remained drawn. The effect of this intervention was not immediate however there was a significant decrease in trend over time of 7% per 4-week period and the authors have suggested that based on previous data they would have expected to see 101 cases over the intervention period, whereas they actually saw 38 cases, a 63% decrease. Asymptomatic carriage has for some time been suggested as a significant risk factor for transmission, as other studies which show high skin contamination from these patients have demonstrated, including studies that have demonstrated a risk from healthcare environments contaminated by asymptomatic patients. Keeping disinfectants with proven sporicidal activity in reserve for only 'cases' of C. difficile may mean that opportunities for reducing the bioburden from asymptomatic patients are missed


Which strategy is most cost-effective in preventing the transmission of C. difficile?

As resources become more and more constrained in healthcare facilities around the world, we need to think in terms of both effectiveness, and cost-effectiveness. A new modelling study published in PLoS ONE evaluates the cost-effectiveness of several strategies to prevent the transmission of C. difficile. Probably the key finding of the study is that hand hygiene compliance, environmental decontamination, and empiric isolation and treatment were the most effective interventions.

The model was a simulation of C. difficile transmission, including estimates for the following parameters: interactions between patients and health care workers; room contamination via C. difficile shedding; C. difficile hand carriage and removal via hand hygiene; patient acquisition of C.
difficile via contact with contaminated rooms or health care workers; and patient antimicrobial
use. Six interventions were then tested either individually or as a bundle at three levels of efficacy (base-case (BASE) to reflect typical hospital practice, (2) intervention (INT) to represent implementation of hospital-wide efforts to reduce C. diffiicle transmission, and (3) optimal (OPT)to represent the highest expected results from strong adherence to the interventions), and at three levels of transmission and importation (low, medium, and high).

Bundled interventions were most cost-effective, and hand hygiene compliance, environmental decontamination, and empiric isolation and treatment were most effective as individual interventions.

This study supports most approaches to C. difficile management, which recommend a bundle of interventions including focus on hand and environmental hygiene, and patient isolation.




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