Linking the Vegetative Cell and Spore Proteomes of Peptoclostridium difficile

Peptoclostridium difficile, an anaerobic pathogen, known as causative agent of pseudomembranous colitis and nosocomial diarrhoea. It can also form highly resistant endospores which lay the basic foundations of infection prior germination in the human guts. P. difficile exploits toxins TcdA and TcdB as well as a plethora of other proteins to infect the host. The present study is exclusively focused on the interconnection between vegetative cell and spore proteomes. A novel method developed for 15N metabolic labelling of P. difficile vegetative cells has enabled mass spectrometric quantification of relative protein levels of this pathogen. A total of 1095 proteins has been identified over the combined spores and vegetative cells. From this 796 proteins have been relatively and reproducibly quantified between spores and vegetative cells. Of the quantified proteins 80% are common to both the vegetative cells and spores, indicating that pathogenic P. difficile employs a relatively modest proteomic changeover for survival. Also of the identified proteins are 20%putative membrane proteins which may provide essential targets to combat P. difficile infections. Detailed data analysis has qualified potential biomarkers for diagnostic purposes.