Team:Sheffield/Human Practices
BrightBiotics as a Diagnostic Tool
The Global Antimicrobial Resistance Issue
When choosing an issue to tackle with our diagnostic hardware, we decided to focus on the growing issue of antimicrobial resistance (AMR). AMR infections are thought to claim as many as 700,000 lives per year, a figure that is expected to rise to 10 million by 2050 if current trends continue (Figure 1) (1). The World Health Organisation (WHO) has therefore described AMR as one of the major concerns of modern healthcare (2), and it is critical that we take action now.
The use of antibiotics is the leading cause of antimicrobial resistance around the world, and in 50% of cases, antibiotic treatment is either not needed or not optimally effective for the infection (3). Doses of antibiotic that are not lethal to bacteria leads to the development of antibiotic resistance by supporting genetic change and acting as a selection pressure (4) (Figure 2). Therefore, one way clinicians can combat AMR is to conduct antimicrobial susceptibility tests (ASTs), to identify any drug resistance in pathogens and ensure effective drugs are chosen for treatments (5).
Advice from Microbiologist Consultants
To gain a better understanding of what ASTs are most commonly used in the clinic, we spoke to microbiologist consultants in Poland and Cyprus. They informed us of the Vitek 2 System, that is commonly used for ASTs.
Vitek2 is a highly automated system, in which a bacterial suspension, grown from a patient sample, is distributed into compact cards containing antibiotics (figure 3). A sensitive optical density system then measures changes in bacterial growth in the presence of the antibiotics in the cards. If there is no bacterial growth, then the organism is sensitive to the drug and it would therefore be an appropriate treatment option.
However, the Vitek 2 system is hugely expensive, costing close to $100,000 (7). The clinicians in Poland and Cyprus expressed to us that this cost was the major drawback of Vitek 2, and means that often smaller hospitals and clinics are unable to afford this state of the art machinery, and therefore miss out on the ASTs that could be crucial to prevent the spread of AMR.
Repurposing the BrightBiotics system as an affordable, automated AST device
Following our research on the Vitek 2 system, we noticed that our device could have many of the same features. It detects bacterial growth as a measure of optical density, and so may therefore detect changes in growth at rates similar to Vitek 2. In addition, we could emulate the Vitek 2 cards by putting antibiotics in the well plate, and seeing how various antibiotics affect growth of a bacterial inoculum.
Firstly, we made sure we could detect differences in growth of antibiotic resistant and sensitive strains in the presence of the appropriate antibiotic, as Vitek 2 can. We engineered antibiotic resistant strains by transforming with biobricks encoding chloramphenicol, kanamycin, carbenicillin and ampicillin resistance. Then used a laboratory automated plate reader to compare their growth with that of of antibiotic sensitive strains, in the presence of antibiotics. We found that with the laboratory plate reader we could see a difference within just a few hours at bacterial concentrations as low as 10^3 CFU/ml (equivalent to 1x10-3 OD) (figure 4). This showed us that it would be possible to differentiate between antibiotic sensitive and insensitive strains, in a time frame that could be clinically relevant.
Next, we confirmed that our device could also differentiate between antibiotic resistant and sensitive strains. …. NEW GROWTH CURVE
Integrated Human Practices to Design an Ideal Device
We then took our Antimicrobial Susceptibility Test prototype to professionals working in clinics and diagnostic settings, the markets we see our device entering. We interviewed them for feedback on our prototype device, and asked for constructive feedback. We have attempted to incorporate as much of their feedback as possible into our current device design:
The Royal Hallamshire Hospital in Sheffield, England
We spoke to senior nurses on the wards of a major hospital in Sheffield. They were enthusiastic about the cost of our device, as it is significantly cheaper than the single use tests they currently use for infections such as MRSA screening. However, they felt that the ~8 hour test time of our device would slow down patient flow on wards. Instead, they suggested we contact diagnostic labs directly, whom the hospital uses to diagnose severe patients staying overnight on the wards.
Liverpool Diagnostics in Liverpool, England
We then turned to a major diagnostic lab in the North of the UK. They highlighted to us the importance of identifying the pathogenic organism, as this will be important in patient care, and also in choosing which antibiotics to test against the organism. For bacterial identification, we investigated several mechanisms such as….**PIOTR BACTERIAL IDENTIFICATION STUFF**
They also suggested we create a way to make our device more tailored to certain types of pathogen. To do this, we will mimic the Vitek2 cards, and design well plates, pre-filled with antibiotic appropriate to a certain group of antibiotics. This will increase the autonomy and ease of use of our device, and as 96 well plates are already a standard consumable, they should be much cheaper to produce than the custom Vitek2 cards.
teaching
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Outreach
We organized an outreach event with the aim of raising awareness about synthetic biology among A-Level students from schools in Sheffield. The day started off with introductory lectures about synthetic biology from Dr. Egbert Hoiczyk, senior lecturer at the University of Sheffield. We then organized a mini iGEM competition where students were divided into teams and had to brainstorm and build their own synthetic biology iGEM device. Following this, teams delivered a presentation about their device to a panel of judges (our advisors). These creative students produced exciting and original solutions to tackle issues such as hemophilia, breast cancer, and plastic recycling, using the power of synthetic biology.
