Conventional wisdom has suggested 2 distinct categories of epidemiologic risk factors in the development of Clostridium difficile infection (CDI): factors that increase the risk of transmission of C difficile and factors that disrupt the patient’s lower intestinal microbiota, a major host defense against infection. This host defense function may be best understood in terms of the expression of these microorganisms’ collective and representative genome, known as the microbiome. Although antibiotics appear to be the major disruptive force of the microbiome in hospitalized patients, evidence indicates that other medications, such as proton pump inhibitors and antidepressants, and chronic conditions, such as obesity,1 may also be associated with microbiome disruption and/or CDI. In addition to increasing the risk of infection, the microbiome disruption from antibiotics may also increase C difficile transmission via increased likelihood of asymptomatic colonization and, once colonized, increasing clonal expansion and domination of the microbiota by C difficile. Meanwhile, there is increasing evidence pointing to the importance of asymptomatic carriers in the transmission of C difficile in hospitals. However, few studies have examined the epidemiology of antibiotics affecting transmission of C difficile among patients, something Brown et al2 have addressed in this issue of JAMA Internal Medicine.
McDonald LC. Uncovering the Role of Antibiotics in the Transmission of Multidrug-Resistant Organisms. JAMA Intern Med. 2015;175(4):633-634. doi:10.1001/jamainternmed.2014.8279