My Dissertation Experience – Emily Clayton

Supervisor and project title:

Professor Roger Pickup: Identification and characterisation of unknown bacteria from mobile phone screens using substrate utilisation analysis

Why I chose this topic:

I have always had a keen interest in the areas of microbiology and cell biology, so I knew I was going to list these topics as my first options for my project. I was luckily given my first choice of microbiology and was given general guidance as to what my project will be on, where I had to choose an environment of my choice to culture bacteria from to ultimately identify.

How much time was spent in the lab?

I spent around 5 weeks completing the lab work for my project, doing lab work every week day starting at 9am and finishing for about 3pm. Time management was key in the microbiology lab to ensure that our samples had enough time to culture and we could carry out other tests in the meantime. Having a lab notebook helped in doing so, and by writing out daily what I completed in the lab and what I was yet to do that week, it ensured I was on track to achieve my aims. This also came in handy when writing up my dissertation, as I could look back on what I did to aid in composing the different sections of my project.

What I investigated:

My project was about culturing bacteria samples taken from the surface of mobile phone touch screens and using substrate utilisation techniques to ultimately determine the species of the bacteria. Once I had grown initial cultures taken from 10 separate phone screens, I then chose distinct colonies to purify using streak plate cultures. After their second purification and incubation at 30°C, I was able to use these colonies to run substrate utilization tests on. I began by carrying out gram stain, oxidase and catalase tests on the 23 bacteria I purified. From these results I then chose 10 of these bacteria to conduct further analysis on. This included the use of differential media such as blood agar, chromogenic agar and MacConkey agar, along with tests to determine the metabolic properties of the bacterium. Different temperatures were tested, motility properties, and API identification. From conducting these tests, I was able to gain a large identification profile of 10 bacteria recovered from mobile phone touch screens.

What I discovered:

I found that half of the bacteria I isolated from mobile phone screens are enteric to human microflora, such as Staphylococcus epidermidis which is a bacterium commonly found on human skin. The rest of the bacteria isolated are commonly found in moist environments and soil, such as Pseudomonas oryzihabitans.  It was evident from my investigation that bacteria found on mobile phone screens not only reflected human microflora as expected, but also portrayed environmental influence. All the bacteria isolated had the potential to act as opportunistic pathogens in immunocompromised patients, with many of the strains showing antibiotic resistance which is currently a large issue in medical environments.

If I could do it again, I would change:

I would ensure to make the most of the summer holidays to make a start on gathering all my results and putting them into tables and figures as this part was very time consuming due to the large amount of data I had to evaluate.

Any hints or advice?

As I said before, be sure to keep a record of your lab work as you go through it, so when you go back to write up your project, you have a chronological timeline of what you completed and the results you found. Make the most of the literature review as it counts for 30% of the dissertation (the biggest weighted section!) and the deadline for this is before summer whilst you are still completing the lab research. Ensure you choose a dissertation topic you are interested in and have possible future career prospects for as this will come in excellent use in applications and interviews as valuable lab and analytical experience in your chosen field.

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