2088. The Role of Surface Adhesins in Clostridium difficile Virulence and Biofilm Formation: Comparison between a Non-Epidemic and an Epidemic Strain 
Session: Poster Abstract Session: Clostridium difficile: Outcomes, Testing, Prevention
Saturday, October 29, 2016
Room: Poster Hall
Background: C. difficile, the causative agent of severe inflammation of the pseudomembranous colitis, has become the most significant nosocomial antibiotic-associated diarrhoea reported worldwide. Recurring infections and increasing antibiotic resistance have complicated treatment of C. difficile infection. Whilst the two major virulence factors, toxins A and B, are widely recognized as essential for C. difficilevirulence, and spores are important for transmission and persistence of infection, other virulence-associated factors such as intestinal colonization and formation of biofilm in the gut undoubtedly contribute to virulence and persistence, but the mechanisms involved in this process have not been well characterized.

Methods: CLosTron and Allelic-exchange site-directd mutagenesis technology was used to inactivate genes involved in biofilm formation, adhesion and colonization. Surface adhesin mutants were assesed for adherence and colonization ability using the in vitrol cell culture model and in four animal models of infection in vivo.

Results: This study showed that for the first time the hypervirulent PCR-ribotype 027 strain forms complex, structured biofilms in vitro. We then investigated the role of selected virulence-associate clostridial proteins in biofilm development, and find that surface factors such as the flagellum and cwp84, are all important for biofilm development. Moreover this study demonstrated that these biofilms can resist high concentrations of vancomycin, an antibiotic that is currently used in treatment of infections.

Conclusion: This study confimed for the first time the ability of hypervirulent strain to form biofilms in the gut and multiple factors (surface adhesins) play importnat roles in biofilm developement and antibiotic resistance. Morover, this study observed for the first time the differences between the ability of epidemic hypervirulent and non-epidemic strain in adherence and intestinal colonization. We showed that the flagellar proteins of hypervirulent strain function as surface adhesins in mediating attachment to human intestinal cells, the first step in intestinal colonization and biofilm formation. On the contrary, the flagella proteins and motility are not needed for colonization by the non-epidemic strain.

Soza Baban, PhD, Molecular Medical Sciences, Clostridia Research Group (CRG), Center for Biomolecular Sciences, The University of Nottingham, Nottingham, United Kingdom

Disclosures:

S. Baban, None

Findings in the abstracts are embargoed until 12:01 a.m. CDT, Wednesday Oct. 26th with the exception of research findings presented at the IDWeek press conferences.