NERC GW4+ DTP PhD studentship: Environmental hotspots of antibiotic resistance.

Main supervisor: Doctor Michiel Vos, University of Exeter, Penryn/Truro Campus, Cornwall

Co-supervisor: Doctor Ruth Airs, Plymouth Marine Laboratory

Co-supervisor: Dr Will Gaze, University of Exeter, Truro Campus, Cornwall

Co-supervisor: Professor Angus Buckling, University of Exeter, Penryn Campus, Cornwall

Co-supervisor: MSc Tim van Berkel, Cornish Seaweed Company

Project Description:

Increasing prevalence of antibiotic resistance in bacteria is a global problem, raising the possibility that we are entering a post-antibiotic era where even the most ordinary infections are untreatable. According to the UK chief medical officer Dame Sally Davies: “There are few public health issues of potentially greater importance for society than antibiotic resistance”.

Selection for antibiotic resistance occurs in the clinic, but also in the environment where antibiotic residues end up through pollution and use in farming. In addition, contamination of the environment with heavy metals selects not only for resistance to these metals but also for resistance against antibiotics (a process termed co- selection). However, there is another potential avenue of antibiotic resistance evolution that has hitherto received very little attention: co-selection through antimicrobial-producing organisms.

Multicellular organisms live in tight association with a ‘microbiome’ which normally provides a range of benefits to the host. However, animals and plants without exception also produce antimicrobial compounds to ward off pathogens. Pathogens are expected to evolve resistance to antagonistic compounds produced by the host, which in turn selects for hosts to evolve novel compounds in a co-evolutionary arms race. By evolving defences against host antimicrobials, pathogenic bacteria could potentially also evolve increased resistance to clinical antibiotics.

Seaweeds are continually exposed to a large variety of potentially harmful microorganisms present in seawater and therefore commonly exhibit strong antimicrobial activity to prevent fouling and disease. It has been long known that seaweed extracts are able to inhibit a wide variety of bacteria. Our recent research on pathogenic Staphylococcus aureus isolates has shown that isolates that are more resistant to clinical antibiotics are also more resistant to seaweed extracts, consistent with co-selection.

In this project, we will test whether bacteria on seaweeds, occurring there naturally or through human contamination, display elevated levels of resistance to seaweed exudates compared to bacteria present elsewhere (i.e. are locally adapted (1)) and whether they are also more resistant to clinical antibiotics. We will use a combination of field sampling, lab mesocosm experiments, metabolomics and molecular biology to quantify seaweed antibiotic activity and bacterial resistance.

It is important to realize that the genetic mechanisms conferring antibiotic resistance are ancient, and must have originated due to non-anthropogenic selective forces. We here use seaweeds as a promising model system to test the importance of biotic selection for the evolution and maintenance of antibiotic resistance in the natural environment.

Entry requirements:

Applicants should have obtained, or be about to obtain, a First or Upper Second Class UK Honours degree, or the equivalent qualifications gained outside the UK. Applicants with a Lower Second Class degree will be considered if they also have Master’s degree. Applicants with a minimum Upper Second Class degree and significant relevant non-academic experience are encouraged to apply. All applicants would need to meet our English language requirements by the start of the project http://www.exeter.ac.uk/postgraduate/apply/english/ The majority of the studentships are available for applicants who are ordinarily resident in the UK and are classed as UK/EU for tuition fee purposes, however up to 9 fully funded studentships across the DTP are available for EU/EEA applicants not ordinarily resident in the UK. Applicants who are classed as International for tuition fee purposes are not eligible for funding.

To apply: http://www.exeter.ac.uk/studying/funding/award/?id=1952