Ward-level antibiotic prescribing is associated with a statistically significant and clinically relevant increase in Clostridium difficile risk, according to the results of a study published in the April 2015 issue of JAMA Internal Medicine. The study, which retrospectively evaluated 34,298 patients age 18 or older who were admitted to one of 16 wards at an acute care teaching hospital form June 2010 to March 2014, found that for every 10% increase in ward-level antibiotic exposure, there was an associated 34% increase in C. difficile incidence. The data indicated that the association between C. difficile incidence and ward antibiotic exposure was the same for all patients whether or not they were recently exposed and that C. difficile risk persisted after adjustments for differences in patient-risk factors among wards. The researchers hypothesize that the marked effects of ward-level antibiotic exposure are likely explained by an increase in the number of patients colonized with, and shedding, C. difficile in wards with high rates of antibiotic use. A high prevalence of antibiotic use could increase environmental contamination and the incidence of C. difficile infection. They note that their conclusion is supported by research indicating that approximately half of C. difficile strains among C. difficile infection cases in hospitals cannot be genetically linked to previously identified symptomatic patients. They suggest that future studies should focus on more clearly describing the mechanisms that link ward-level antimicrobial use and infection incidence and conclude that their findings strongly support the further funding and development of hospital antibiotic stewardship programs. An accompanying editorial discusses the study's results and the importance of understanding how antibiotics can increase the risk of transmission of multidrug-resistant organisms.

HRC Recommends: Many individuals and groups throughout a hospital share responsibility for infection prevention and control. Coupled with increased concerns over antibiotic resistance (see the April 1, 2015, HRC Alerts), the information on C. difficile infection presented in the study above makes a compelling case for organizations to adopt strong antibiotic stewardship programs. While infection control and antibiotic stewardship are not direct responsibilities for most risk managers, risk managers should meet regularly with the facility's infection preventionist or infection prevention committee to discuss risks, trends, the effectiveness of existing interventions, and potential future interventions. Risk managers should also assess the hospital's exposure to financial and tort liability related to infections and ensure that the infection prevention program has adequate staff, expertise, infrastructure, resources, and administrative and other support.