Date on Senior Honors Thesis


Document Type

Senior Honors Thesis



Degree Program

College of Arts and Sciences

Author's Keywords

Clostridium difficile; Evolutionary medicine; Ribotype 027; Virulence


The emergence of virulent, antibiotic-resistant Clostridium difficile ribotypes over the past thirty years has greatly concerned both the medical and research communities. As of 2010, C. difficile has surpassed methicillin-resistant Staphylococcus aureus (MRSA) as a cause of nosocomial infections and is now found in both healthcare settings and outside communities in the United States. Attendant-borne transmission in hospitals has been associated with the evolution of increased virulence in other nosocomial pathogens, but evolutionary theory has yet to be applied to the epidemiology and virulence of C. difficile. Differences between nosocomial C. difficile infections (CDI) and community-associated CDI (CA-CDI) mortality and ribotype distributions were evaluated in order to determine if attendant-borne transmission in hospitals and long-term care facilities favors highly virulent C. difficile ribotypes. Analysis of the current literature on C. difficile revealed that nosocomial CDIs were significantly more virulent and associated with greater mortality than CA-CDIs. Additionally, the data indicate that ribotypes 027 and 001/smz are particularly well-adapted for transmission in healthcare settings given their prominent role in nosocomial CDI but near absence in healthy C. difficile carriers in the outside community. These findings suggest that interventions that prevent attendant borne transmission may aid in the incidence reduction and virulence modification of C. difficile infections.

Included in

Biology Commons