Dental unit water lines as reservoirs for antimicrobial resistance gene dissemination

One fully funded Frederick E Hopper full-time PhD scholarship is available in the School of Dentistry for a start in October 2025. The scholarship will cover UK tuition fees and attract a stipend matching the UKRI rate (£19,237 for 2024/25), subject to satisfactory progress.<br /> The award is open to full-time or part-time candidates (UK only) who meet the eligibility for a place on a PhD degree at the School of Dentistry. This project would suit a student with a background in physical science with interest in biological systems, or in biological science with an interest in physical techniques.

<p>Dental equipment often relies on water feeds for cooling and irrigation during oral procedures. The narrow bore tubing used has a high surface area and holds stagnant water during non-operational periods, creating an ideal environment for microorganisms. These bacterial populations harbour antimicrobial resistance (AMR) genes, which pose significant healthcare challenges. Microbial contamination of dental unit waterlines (DUWL) is widely reported, (1, 2) making it a significant infection control issue. Even non-pathogenic organisms can harbour AMR genes, with the potential to transfer these elements to harmful organisms. High-speed dental instruments produce aerosols, which can disseminate microorganisms into the air, posing a threat to clinicians and patients. (3) The AMR genes carried by these bacteria can then be transferred within the diverse oral community and potentially to the gut. (4)<br /> Evidence shows that bacterial contamination of DUWLs occur, and that AMR elements can transfer between bacteria. However, little is known regarding AMR gene dissemination via dental aerosols. This study will explore the relationship between the DUWL resistome and its potential transfer to patients and clinicians.</p> <h5>Experimental Approach</h5> <p>DUWL samples will be collected from patient facing clinics and dental simulation labs to represent different levels of proximity, disinfection, and potential exposure. Aerosol modelling will be used in dummy simulations of clinical procedures, with strategically positioned filter papers and biological air samplers to collect aerosolized microorganisms. (3) DNA will be extracted and analysed using in-house bioinformatics pipelines and publicly available databases to identify AMR genes. Comparisons of pre- and post-decontamination will outline its efficacy.</p> <h5>Aims & Objectives</h5> <p>In the wake of the COVID-19 pandemic, the impact of dental aerosols is more apparent. Their potential involvement in AMR gene dissemination is crucial to understand. Therefore, in alignment with WHO priorities in tackling AMR, it is now appropriate to investigate undiscovered reservoirs burdening our healthcare systems.</p> <ul> <li>Characterize AMR genes in DUWLs at a large dental school setting.</li> <li>Assess the risk of AMR gene transfer from DUWLs to patient mouths via dental tools.</li> <li>Quantify aerosolized AMR genes during various dental procedures.</li> <li>Investigate the impact of decontamination processes on AMR genes.</li> </ul> <h5>References</h5> <ol> <li>Wirthlin MR, Marshall Jr GW, Rowland RW. Formation and decontamination of biofilms in dental unit waterlines. Journal of periodontology. 2003;74(11):1595-609.</li> <li>Szymanska J, Sitkowska J, Dutkiewicz J. Microbial contamination of dental unit waterlines. Annals of Agricultural and Environmental Medicine. 2008;15(2).</li> <li>Vernon JJ, Black EVI, Dennis T, Devine DA, Fletcher L, Wood DJ, Nattress BR. Dental Mitigation Strategies to Reduce Aerosolization of SARS-CoV-2. Journal of Dental Research. 2021:00220345211032885.</li> <li>Lerminiaux NA, Cameron ADS. Horizontal transfer of antibiotic resistance genes in clinical environments. Canadian Journal of Microbiology. 2019;65(1):34-44.</li> </ol> <h5>Other Conditions</h5> <ul> <li> <p>Applicants must not have already been awarded or be currently studying for a doctoral degree.</p> </li> <li> <p>Awards must be taken up by 1st October 2025.</p> </li> <li> <p>Applicants must live within a reasonable distance of the University of Leeds whilst in receipt of this scholarship.</p> </li> </ul>

<p>To apply for this scholarship opportunity applicants should complete an <a href="https://medicinehealth.leeds.ac.uk/faculty-graduate-school/doc/apply-2">online application form</a> and attach the following documentation to support their application. </p> <ul> <li>A full academic CV</li> <li>Degree certificate and transcripts of marks</li> <li>Evidence that you meet the University's minimum English language requirements (if applicable)</li> </ul> <p>To help us identify that you are applying for this scholarship project please ensure you provide the following information on your application form;</p> <ul> <li>Select PhD in Dentistry as your programme of study</li> <li>Give the full project title and name the supervisors listed in this advert</li> <li>For source of funding please state you are applying for a Frederick E Hopper Scholarship</li> </ul> <p>If English is not your first language, you must provide evidence that you meet the University's minimum English language requirements (below).</p> <p><em>As an international research-intensive university, we welcome students from all walks of life and from across the world. We foster an inclusive environment where all can flourish and prosper, and we are proud of our strong commitment to student education. Across all Faculties we are dedicated to diversifying our community and we welcome the unique contributions that individuals can bring, and particularly encourage applications from, but not limited to Black, Asian, people who belong to a minority ethnic community, people who identify as LGBT+ and people with disabilities. Applicants will always be selected based on merit and ability.</em></p>

Applicants to this scholarship in the School of Dentistry should normally have an Undergraduate degree of 2:1 or above (or international equivalent) in a relevant subject area. A Master’s degree is desirable, but not essential.

The minimum English language entry requirement for postgraduate research study in the School of Dentistry is an IELTS of 6.5 overall with at least 6.0 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid.

<p>We are offering 1 full-time PhD scholarship in the School of Dentistry for one UK candidate, covering a maintenance grant matching the UKRI stipend rate (£19,237 for 2024/25) and UK tuition fees for three years, subject to satisfactory progress. The award will be made for one year in the first instance and renewable for a further period of up to two years, subject to satisfactory academic progress. This is one of seven available projects being advertised for the one successful candidate for this scholarship. </p>

<p>For further information please contact the Faculty PGR Admissions Team</p> <p>e: <a href="mailto:fmhpgradmissions@leeds.ac.uk">fmhpgradmissions@leeds.ac.uk</a></p>