C-di-GMP regulation of a novel collagen-binding surface protein in Clostridium difficile
3rd International Congress on Bacteriology and Infectious Diseases
August 04-06, 2015 Valencia, Spain

I-Hsiu Huang1, Tung Sheng Lin1, Zih-Cian Su1 and Guan-Yu Chen2

Posters-Accepted Abstracts: J Bacteriol Parasitol

Abstract:

Clostridium difficile is a gram positive, spore forming obligate anaerobic bacteria and is the leading cause of the nosocomial
antibiotic associated diarrhea. C. difficile infection (CDI) results in diarrhea and severe pseudo membrane colitiss (PMC)
and toxic mega-colon. Before pathogens can cause diseaseitneeds to attach to the host cell first. Therefore, our studies focus
on non-toxin virulence factors responsible for C. difficile colonization. By bioinformatics analysis, orfCD2831 was predicted
to encode for a large collagen-binding protein on the surface of C. difficile and was renamed as Cell surface protein 1 (Csp1).
ELISA studies demonstrated that recombinant Csp1 binds specifically to collagen Type I. Previous in vitro studieshas revealed
that the metalloprotease CD2830 cleaves Csp1. Cyclic diguanylate(3’, 5’cyclic diguanylic acid) (c-di-GMP), a secondary
messenger regulates the virulence and biofilm formation in many bacterial pathogens.Transcriptional analysis has indicated
that c-di-GMP can increase the transcriptional level of Csp1 while down regulate CD2830 through riboswitches. The aim
of our study then was to elucidate the relationship between c-di-GMP, CD2830 and Ccsp1 in C. difficile. In our preliminary
data, we used cell fractionation and Western blot to analyze the localization of Csp1. Csp1 was found mostly secreted into the
culture supernatant rather than on the cell wall under laboratory condition.Inactivation of CD2830 shifted the localization
profile of Csp1 toward cell wall anchoring suggesting that Csp1 is secreted via cleavage by CD2830. Next, artificial induction
of the cytoplasmic c-di-GMP level in C. difficile resulted in overexpression and prominent cell wall localization of Csp1. In
summary, we have identified a novel collagen-binding surface protein in C. difficile that is bi-regulated by a metalloprotease
and the secondary messenger c-di-GMP. Future works will focus on unraveling the role of Csp1 in C. difficile pathogenesis
using animal studies.

Biography :

I-Hsiu Huang is an Assistant Professor at Department of Microbiology and Immunology Medical College, National Cheng Kung University, Taiwan.