Team:Oxford/Test/Project
[PROJECT]
overview
The World Health Organisation have recently (May 2015) endorsed a global action plan to tackle antimicrobial resistance.
The plan sets out 5 objectives:
- Improve awareness and understanding of antimicrobial resistance
- Strengthen surveillance and research
- Reduce the incidence of infection
- Optimize the use of antimicrobial medicines
- Ensure sustainable investment in countering antimicrobial resistance
Antimicrobial resistance is a complex problem driven by many interconnected factors. As such, single, isolated interventions have little impact. Coordinated action is required to minimize emergence and spread of antimicrobial resistance.
Our solution to antimicrobial resistance is to turn bacteria on themselves. Although bacteria are generally thought of as causing infection, most bacteria that live inside the human body are non-pathogenic and some of them can be turned, after proper engineering, into ‘smart’ living therapeutics that have the potential to treat a diverse range of diseases. We are focused specifically on treating urinary tract infections (UTIs). Resistance to one of the most widely used antibacterial drugs for the oral treatment of urinary infections caused by E. coli – fluoroquinolones – is now widespread and, with UTIs being the most commonly acquired infection at hospital, there is a huge need to find a solution for the treatment of UTIs and resistance to antimicrobial resistance.
How?
We are working on a novel antimicrobial strategy that uses engineered avirulent E. coli to treat UTIs, which are caused by uropathogenic bacteria and the biofilm that they form in the urinary tract. By employing engineered E. coli, we can create a system that offers persistent protection against biofilm formation in the urinary tract and on the surface of catheters without the use of antibiotics.
“While there is a lot to be encouraged by, much more work needs to be done to combat one of the most serious global health threats of our time.”
Dr Keiji Fukuda
WHO’s Assistant Director-General for Health Security
The project aims to investigate how bacterial biofilm disrupting proteins can be exported from E. coli. The proteins DispersinB, MicrocinS, DNase and Endolysin will be expressed from commercial pBAD expression vectors with N-terminal fusion tags to target them for export via the DsbA, YebF and flagellar export pathways in E. coli. Additionally, the holin gene will be expressed under the control of bacterial quorum sensing responsive promoters (in conjunction with the endolysin) to cause host cell lysis and release of these proteins from the cytoplasm on detection of a high target cell density.
What?
Antimicrobial resistance is an increasingly serious threat to global public health and is an issue in all parts of the world, and one of the ways through which bacteria confer themselves protection against antimicrobial drugs is the growing of biofilms. Biofilms, or “bacterial slime”, are responsible for a whole host of medical, industrial and environmental problems that are very costly and technically challenging to remedy. The scale of the problem is huge, with up to 80% of all infections involving the formation of a biofilm. Some examples where biofilms pose especially big an issue are urinary tract infections (UTIs), catheter and implant infections, dental plaque formation as well as infections in cystic fibrosis patients. In industry and infrastructure, biofilms are also the main culprit behind the fouling of various plants and pipelines for aquaculture, water treatment, and food production.
Both antimicrobial resistance and the other problems associated with biofilm formation are big issues in their own right but are especially problematic when they’re combined. The bacteria, already constantly evolving to afford themselves more innate resistance against antibiotics, produce biofilms as protective layers that shield them from the drugs even more comprehensively.
How are we proposing to solve the problem?
There is currently no commercial antibiotic that specifically targets bacterial biofilms, but researchers have identified a range of bacterially-derived biomolecules that degrade and destroy biofilms. As such, our project involves the engineering of bacterial strains to make them produce and secrete enzymes that can destroy the pathogenic bacteria and the biofilms they make. The beauty of the anti-biofilm agents we plan to use is that they have been shown not to induce resistance in the target bacteria, meaning that having them continually produced at a low level will not be nearly bad as with traditional antibiotics. Our system is applicable to a whole host of biofilm environments and with a simple design that can be used in multiple sectors, we hope to get a step further in providing a novel approach to treating microbial infections.
In terms of product formulation and design, we hope to ultimately arrive at a functional proof-of-concept e.g. an enzyme-secreting infection-clearing catheter or a modular system that continuously and cheaply cleans out pipelines.