Identifying the parasitic or passenger role of Blastocystis, in patients with gastrointestinal diseases

Blastocystis is one of the most common intestinal eukaryotic microbes in the human gut. The World’s Health Organization estimates that almost 1 billion people worldwide harbour Blastocystis in their intestines. Despite this prevalence, very little is known about its genetic diversity and pathogenicity, mainly because of its unique appearance that resembles a small grey ball, but also due to its sensitivity to oxygen. It has now become clear that this organism, though morphologically identical, has no less than 17 subtypes (STs) separated by at least a 5% divergence in the small subunit of ribosomal RNA gene. Thus, what we traditionally used to call Blastocystis is really a cluster of several different species. The cluster is now known as the Blastocystis hominis species complex. Reports on the pathogenicity of Blastocystis are conflicting; some claim no visible damage to the epithelial/mucosal layer of the host while others report gross pathology and connection with patients with Inflammatory Bowel Diseases (IBD; e.g. Irritable Bowel Syndrome, IBS). Recent publications have proposed that this is due to the differential degree of virulence of the various subtypes. The degree of pathogenicity, diversity and clinical outcomes of the STs remain unknown and highly debated. In addition, the association between Blastocystis subtypes and the rest of the microbiome is still questionable. This PhD project will provide fundamental information on the pathogenicity of Blastocystis and its effect on the human gut microbiome.

Human gut microbiome studies are mainly bacteria- and archaea-oriented, overlooking the presence of single-cell eukaryotes such as Blastocystis, an enteric microbe with worldwide distribution. The successful PhD candidate will survey the prevalence and subtype variation of Blastocystis in faecal samples collected from UK population cohort and compare them with other national and international surveys. He/she will assess potential links between Blastocystis subtypes and identified microbiota–host covariates and quantified microbiota differentiation relative to subtype abundances and metabolite differences.

Results from this PhD project will have potential implications on clinical practice in the foreseeable future. Current clinical consensus for faecal transplantation recommends the exclusion of donors of samples that are positive for Blastocystis. This study will also demonstrate which Blastocystis subtype could be associated with markers of a healthy gut microbiota in UK population. Subsequently, it will provide suggestions for further investigations to resolve the assumed pathogenic potential of Blastocystis. Since the presence of Blastocystis subtypes varies between different populations and correlates with the rest of the microbiome, our findings will allow for clinical applications related to UK human gut microbiota findings to include the evaluation of individuals’ stratification based on Blastocystis subtypes. The prospective PhD student will be trained and have access to state-of-the-art facilities within the School of Biosciences at University of Kent, including Cell Imaging facility, Biomolecular Science and Biological NMR and will also collaborate with clinicians at the East Kent Hospitals University Foundation Trust. This is a Kent Health-funded PhD project in collaboration with Dr. Mark Shepherd (University of Kent) and Dr. Matthew Strutt from the Pathology Department at the East Kent Hospitals University Foundation Trust.

The candidate: We are seeking a highly-motivated individual, excited by the prospect of conducting cutting-edge research, with a minimum of 2:1 degree and/or a postgraduate degree in a relevant subject. She/he will have a strong willingness to work at the interface of wet-lab, field work and bioinformatics, and demonstrate enthusiasm to learn new skills. Informal enquiries can be addressed to Dr. Anastasios Tsaousis: [Email Address Removed]

How to apply: Applications can be made using the online University application page where the project title should be entered as the proposed area of research and Dr Anastasios D. Tsaousis as supervisor. Please include a CV and a cover letter. Applications must be received by 22nd of April 2019. The start date is 16th of September 2019.