Intervention cuts incidence of healthcare-associated C difficile infection

Last Updated: 2016-04-25

By Megan Brooks

NEW YORK (Reuters Health) - Screening and isolating asymptomatic carriers of Clostridium difficile at hospital admission led to a decline in cases of healthcare-associated C diff infection (HA-CDI) at a Canadian acute care facility.

"The intervention is simple and could be easily implemented in other institutions. If confirmed in subsequent studies, isolating asymptomatic carriers could potentially prevent thousands of cases of HA-CDI every year in North America," the study team concludes in their paper, online April 25 in JAMA Internal Medicine.

Over roughly 17 months, the researchers conducted rectal sampling of all patients admitted through the emergency department of the Quebec Heart and Lung Institute in Quebec City. C diff testing was performed using a polymerase chain reaction assay targeting the toxin B (tcdB) gene of C diff, which has been shown to identify a subset of carriers with a heavier organism load who are more likely to contaminate the skin or environment.

Among the nearly 7,600 patients who were screened, 368 (4.8%) were identified as asymptomatic carriers and isolated for their entire hospital stay.

During the intervention, the incidence rate of HA-CDI fell by more than 50%, from 6.9 per 10,000 patient-days before the intervention to 3.0 per 10,000 patient-days, report Dr. Yves Longtin of the Jewish General Hospital and McGill University in Montreal and colleagues.

They estimate that the intervention prevented 63 of 101 expected cases. To prevent one HA-CDI, 121 patients had to be screened and six asymptomatic carriers had to be isolated, they note.

During the intervention period, there was no significant decrease in the incidence of HA-CDI among other hospitals in Quebec City and throughout Quebec province.

The researchers say their study is limited by the single-center design and the findings need to be replicated in additional studies.

Also, the cost-benefit ratio of the screen-and-isolate strategy is unknown, but preliminary estimates suggest it may be cost-effective. The intervention cost US$130,000 and prevented 63 cases and the estimated savings from averting CDI cases was greater than the cost of the intervention.

In email to Reuters Health, Dr. Longtin said, "The study is still ongoing at the Quebec Heart and Lung Institute. After 30 months of intervention, the institutional C difficile infection rates are still extremely low - the lowest among all university hospitals in the Province of Quebec. The nosocomial C difficile infection incidence rate for the most recent fiscal year was approximately 2 cases per 10,000 patient-days."

"The intervention is fairly simple to implement for any institution that has access to an assay that is sufficiently sensitive to detect asymptomatic carriers of C difficile," Dr. Longtin added. "Each of the components of the intervention are already in place in most hospitals. For example, the screening is similar to another type of screening used in many hospitals to detect carriers of vancomycin resistant Enterococcus (VRE), and the components of isolation precautions are similar to those used in many hospitals for other multi-resistant bacteria such as MRSA."

"The results of this study are promising for reducing HA-CDI," write Dr. Alice Y. Guh and Dr. L. Clifford McDonald, of the U.S. Centers for Disease Control and Prevention in a linked editorial.

They say the feasibility of implementing active surveillance for C diff needs to be considered carefully and practical challenges and disadvantages to implementing active surveillance and isolation precautions also exist.

Nonetheless, this study shows the "possible benefit of using active surveillance testing and isolation of asymptomatic carriers for preventing HA-CDI. Larger, well-designed studies, such as cluster randomized trials, are ultimately needed to confirm the effectiveness of this strategy," they conclude.

The study had no commercial funding. Dr. Longtin is a coapplicant on a patent held by The Royal Institution for the Advancement of Learning/McGill University on methods, reagents and kits for the assessment of bacterial infections.

SOURCE: http://bit.ly/1QxaOvT and http://bit.ly/1NLRhIh

JAMA Intern Med 2016.