Terrestrial Clostridium difficile phages and genomic characterization of two myoviruses.


Srwa Rashid1, Jakub Barylski2, Katherine Hargreaves3, Andrew Millard4, Martha Clokie1

1Department of Infection, Immunity and Inflammation, Medical Sciences Building, university of leicester, Leicester, United Kingdom
2Department of Molecular Virology, Faculty of Biology, Adam Mickiewicz University, Poland, Poznan, Poland
3Department of Microbiology, The Ohio State University, OH, 4201,, Ohio, United States
4Microbiology & Infection Unit, Warwick Medical School, University of Warwick, Coventry, United Kingdom


Clostridium difficile is a Gram positive, spore-forming, anaerobic bacterium, which can cause infectious diarrhoea (termed C. difficile Infection; CDI) which in severe cases leads to pseudomembranous colitis. CDI usually occurs as following antibiotic treatment that decreases the intestinal microbiota diversity, allowing C. difficile to proliferate and cause disease. In the last ~15 years, the epidemiology of CDI has changed considerably with the rapid emergence of hypervirulent strains; this raises concerns regarding the evolution of virulence and antibiotic resistance. The lack of effective antibiotics for C. difficile has prompted researchers to seek alternative ways to combat the pathogen. One approach is phage therapy. A group of phages infecting C. difficile were isolated from the poorly studied soil and sediment ecosystems in the north of Iraq. The phages are members of the Siphoviridae (12/14) and Myoviridae (2/14). The myoviruses, CDKM15 and CDKM9, were selected for further characterization as candidate therapeutic phages due to their broad host ranges that include clinical relevant strains. CDKM9 and CDKM15 infect 25 isolates from 13 ribotypes, and 20 isolates from 9 ribotypes, respectively. This includes the major epidemic isolates of PCR ribotypes 001, 014, 014/020 as well as 005 and 027. Genome analysis revealed that CDKM15 has a CRISPR array with spacers perfectly match to ϕCD505 (a long tailed myovirus that isolated form a spatially distant source). This observation has implications for our understanding on the global evolution of this pathogen in these reservoirs and across the globe. Furthermore, an analysis of the TerL packaging ATPases of these phages suggests that they may package their genomes into capsids using a previously unknown mechanism. Together, these data show that these phages extend the current known diversity of phages infecting this important human pathogen.






Reference:
Posters Day 2-T03-Pos-43
Session:
Posters Covering Ecology, Host population control, Co-Evolutionary dynamics and Subversion/Evasion of Host Defences
Presenters:
Srwa Rashid
Session:
Day 2 Posters Covering: Ecology, Host population control, Co-evolutionary dynamics and Subversion/Evasion of host defences
Presentation type:
Poster presentation
Room:
Poster Halls
Date:
Tuesday, 19 July 2016
Time:
12:05 - 15:00