Team:LMU-Munich/Rathenau

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By utilizing QS-dependent promoters, BaKillus will activate pathogen-killing devices like the production of antimicrobial peptides or biofilm degrading enzymes in the presence of target pathogens (see Fig. 1 for details). As a safety measure, a delayed suicide-switch guarantees non-persistence of genetically modified B. subtilis in the absence of pathogens.  
By utilizing QS-dependent promoters, BaKillus will activate pathogen-killing devices like the production of antimicrobial peptides or biofilm degrading enzymes in the presence of target pathogens (see Fig. 1 for details). As a safety measure, a delayed suicide-switch guarantees non-persistence of genetically modified B. subtilis in the absence of pathogens.  
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[[File:LMU14_Application_Rathenau_BaKillus_Overveiw.png|frame|700px|center|
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[[File:LMU14_Application_Rathenau_BaKillus_Overveiw.png|thumb|700px|center|
Figure 1: Basic concept of BaKillus: S aureus and S pneumoniae use autoinducer-peptides (AIP) for cell-density dependent regulation of gene expression (quorum sensing), e.g. regulation of pathogenicity. BaKillus with the respective two-component sensing systems AgrAC and ComDE is enabled to activate killing devices in an AIP dependant manner. Uncommon antimicrobial peptides like subtilin or the cannibalism toxin, the peptidase lysostaphin and the hydrolase dispersin will be used to ensure effective killing of the targeted pathogens.
Figure 1: Basic concept of BaKillus: S aureus and S pneumoniae use autoinducer-peptides (AIP) for cell-density dependent regulation of gene expression (quorum sensing), e.g. regulation of pathogenicity. BaKillus with the respective two-component sensing systems AgrAC and ComDE is enabled to activate killing devices in an AIP dependant manner. Uncommon antimicrobial peptides like subtilin or the cannibalism toxin, the peptidase lysostaphin and the hydrolase dispersin will be used to ensure effective killing of the targeted pathogens.
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Revision as of 11:38, 5 September 2014


Contents

Collaboration with the Rathenau Institute

Application Scenario

Download our application scenario as a PDF here.


The BaKillus Concept

Increasing bacterial resistance to classical antibiotics remains a serious threat and urges the development of novel pathogen-killing strategies to treat infectious diseases. Exploiting bacterial communication mechanisms such as quorum sensing is a promising strategy to specifically target certain pathogens. Towards this goal, the synthetic organism BaKillus was designed to specifically target respective QS-dependent pathogenic bacteria. Here, the core element is a pathogen-detection device to detect Staphylococcus aureus and Streptococcus pneumoniae. By utilizing QS-dependent promoters, BaKillus will activate pathogen-killing devices like the production of antimicrobial peptides or biofilm degrading enzymes in the presence of target pathogens (see Fig. 1 for details). As a safety measure, a delayed suicide-switch guarantees non-persistence of genetically modified B. subtilis in the absence of pathogens.

Figure 1: Basic concept of BaKillus: S aureus and S pneumoniae use autoinducer-peptides (AIP) for cell-density dependent regulation of gene expression (quorum sensing), e.g. regulation of pathogenicity. BaKillus with the respective two-component sensing systems AgrAC and ComDE is enabled to activate killing devices in an AIP dependant manner. Uncommon antimicrobial peptides like subtilin or the cannibalism toxin, the peptidase lysostaphin and the hydrolase dispersin will be used to ensure effective killing of the targeted pathogens.

Application

BaKillus could be applied in two independent ways, first as a point-of-care diagnostic tool to identify pathogens and second, as a drug-producing microbe to treat bacterial infections.

Pathogen-identification diagnostic tool:

Problem:

Current tests to identify S. aureus (e.g. coagulase) require a time-consuming (18-24h) culturing step.

The BaKillus S. aureus diagnosis tool:

If the S. aureus detection device is sensitive enough, a smear of a patient into the BaKillus diagnostic tool would be enough to verify a S. aureus (MRSA) infection. This culture-independent detection provides results within 1-2 hours (just limited by the time for BaKillus spore germination and gene expression) and subsequent treatments could be initiated more quickly. We are planning to develop a ready-to use diagnosis tool for point-of-care testing by the professional staff in hospitals, pharmacies or medical offices (see Fig. 2). We are looking into collaboration with the iGEM-Team Aachen, who are planning something similar (https://2014.igem.org/Team:Aachen).


Figure 2: Basic concept of the BaKillus diagnostic tool. BaKillus spores are stored separately in a self-contained device. About one hour before use, spores and medium are mixed and incubated for the germination of the spores. The sample of a patient (e.g. a smear) can be applied into the culture and after about 30 minutes the result can be analysed with a simple camera-computer-station.


Table 1: Discussion of the BaKillus diagnostic tool.
Strengths Weaknesses
Detection & Identification of AIP dependent pathogens Application is limited to targets that exhibit QS-dependent pathogenicity.
Initial assessment of the sensitivity of the test and tests for reliability of the tool required
Self-contained/tightly closed device prevents release of GMO and thus a product possibly has little legal barriers for approval. (This is topic of an ongoing discussion with Dr. Ulrich Ehlers (Commissioner for GMO-release in Germany, BVL) and Dr. Hans Schrubar (Commissioner for Bio-Safety in Bavaria)
Easy engineering and handling of the detection devic Maybe too cost-intensive due to the need of high-end technology for measurement, especially for the utilization in developing countries. We seek to minimize this hurdle by using low-cost hardware (e.g. Raspberry Pi instead of a conventional computer).

Pathogen treatment tool:

Problem:

Unreasonable use of antibiotics reinforces the propagation of bacterial resistance and globalization of the failure of classic antibiotics to treat bacterial infections.

The BaKillus pathogen treatment tool:

Based on the pathogen-detection device, BaKillus will activate its pathogen-killing devices (see Fig. 1) to kill S. aureus or S. pneumoniae. Both are often associated with surface infections of the human body system and thus BaKillus could be used to cure infected patients. We discussed potential applications with doctors and immunologists and plan an application as a nasal injection to treat chronic inflammation of the ENT tract.

LMU14 Application Rathenau BaKillus Nasal Spray.png
Table 2: Discussion of the BaKillus nasal spray.
Strengths Weaknesses
Novel antibiotics allow treatment of resistant superbugs like MRSA Unknown efficiency and interaction of the drugs with the human body system, therefore individual evaluation and approval required for each novel antibiotic.
Local treatment dependent on presence of pathogen => no need for broad spectrum-antibiotics
Combination of drugs allows effective killing and little survival of resistant subpopulations Strong legal regulations to use GMOs on humans could make the approval a long endeavour and obstruct the substitution of sensing and killing devices for personalized needs, as individual approval is required.
Low production costs Immense costs to fulfil legal regulation for approval and clinical studies
Bacillus subtilis is Generally Recognized As Safe (GRAS status, FDA), so BaKillus is probably non-pathogenic. Additionally, the Suicide Switch and the Trytophane auxotrophy add addtional safety layers.

The gene safety discussion:

Using GMOs for any kind of application requires a detailed consideration about risks and legal regulations. The diagnostic tool does not release the GMO and the approval might be feasible in near future, whereas the use of BaKillus as a nasal spray faces huge legal barriers to be overcome and is unlikely to come into the market in the near future. Necessary steps (timeline) and legal regulations (paragraphs) for an approval of both products will be part of our application wiki. We are in an ongoing discussion with Dr. Ulrich Ehlers (Commissioner for GMO-release in Germany, BVL), Dr. Hans Schrubar (Commissioner for Bio-Safety in Bavaria) and Dr. Gabriele Wanninger (Expert for clinical studies in Bavaria).


Realisation:

In view of the possible BaKillus application process, we first plan to focus on the development of the diagnostic tool inside the university. Funding might be possible by DFG or SynBio- or entrepreneurship-funding organizations. Once our idea is able to leave the lab, we would start a business and develop a prototype with the help of an industry partner (e.g. a small engineering company) and venture capital funds. Alternatively, we would look into the possibility of acquiring the necessary financial means through a crowdfunding campaign. Throughout the development process, we would apply rapid prototyping techniques such as 3D printing to quickly reach a market-ready product. At the same time, intellectual property (e.g. patents) will be built up to protect our invention and provide an income for the growth of our start-up. Through the success of our diagnostic tool, we can convince further investor and finally could be able to afford the approval process of the BaKillus nasal spray. Once we have brought this product to the market, we can push for new legal regulations regarding the approval of SynBio products.