A Taxonomic Review of Clostridium difficile Phages and Proposal of a Novel Genus, "Phimmp04likevirus"

Currently, only three phages that infect the medically important bacterium Clostridium difficile have been discussed by the International Committee of Viral Taxonomy (ICTV). They are all myoviruses, and have been assigned to the genus “phicd119likevirus”. An additional nine phages have since been described in the literature with their genome data available. The Phicd119likevirus is named after the type species: the myovirus ΦCD119 which was the first C. difficile phage to be sequenced. The two additional myoviruses, ϕCD27 and φC2, also fall into this genus based on the similarity of their genome and morphological characteristics. The other nine phages have not been assigned to this genus, and four of them do not fit the criteria for the current taxonomic grouping. We have applied protein clustering analysis to determine their phylogenetic relationships. From these results we propose an additional myoviridae genus, that we term “phiMMP04likevirus”

Metabolite profiling of Clostridium difficile ribotypes using small molecular weight volatile organic compounds

Volatile organic compounds (VOCs) emitted by cultures of ten different Clostridium difficile ribotypes have been profiled using proton transfer reaction-time of flight-mass spectrometry. A total of 69 VOCs were identified and combinations of these VOCs were found to be characteristic for each of the ribotypes. The VOC patterns, with the aid of a statistical analysis, have been shown to be useful in distinguishing different ribotypes. A tentative assignment of different masses also shows that different ribotypes have markedly different emissions of methanol, p-cresol, dimethylamine and a range sulfur compounds (ethylene sulfide, dimethylsulfide and methyl thioacetate), which point to VOCs as potential indicators of different metabolic pathways in virulent and less-virulent strains. The results establish the potential of detecting emitted VOC metabolites to differentiate between closely related C. difficile ribotypes and in the longer term provide metabolic insight into virulence

An Investigation into the Inactivation Kinetics of Hydrogen Peroxide Vapor Against Clostridium difficile Endospores

C. difficile spores are resistant to routine cleaning agents and are able to survive on inanimate surfaces for long periods of time. There is increasing evidence of the importance of the clinical environment as a reservoir for pathogenic agents and as a potential source of healthcare-associated infections (HCAIs). In this context, to reduce the risk of cross-transmission, terminal disinfection of hospital wards and isolation rooms using hydrogen peroxide vapor (HPV) is attracting attention. Spores of C. difficile (ribotype 027) were exposed to constant concentrations of HPV ranging between 11 and 92 mg m3 (ppm) for a range of exposure times in a specially designed chamber. The inactivation data thus obtained was fitted using the modified Chick–Watson inactivation model to obtain decimal reduction values (D values). D values ranged from 23 to 1.3 min at HPV concentrations of 11 and 92 ppm, respectively. We present a simple mathematical model based on the inactivation kinetic data obtained here to estimate the efficacy of commercial HPV processes used in healthcare environmental decontamination. C. difficile spores showed linear inactivation kinetics at steady HPV concentrations ranging between 10 and 90 ppm. The data obtained here was used to provide estimates of the inactivation efficacy of commercial HPV process cycles, which employ unsteady HPV concentrations during the decontamination process