Application Scenario

Download our application scenario as a PDF here.

The BaKillus Concept

Ever increasing microbial resistance to classic antibiotics urges the development of novel pathogen-killing strategies to treat infectious diseases. Exploiting bacterial communication mechanisms such as quorum sensing (QS) 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) or competence stimulating peptide (CSP), respectively, for cell-density dependent regulation of gene expression (quorum sensing), e.g. regulation of pathogenicity. BaKillus with the respective two-component sensing systems AgrAC or ComDE, respectively is enabled to activate killing devices in an AIP or CSP 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.

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 are PCR based to detect specific genes. Theoretically, a PCR-result could be obtained within three hours, whereas it takes round seven hours in practice. However, PCR based methods are error-prone and therefore verification by molecular biologic test are recommended. Current biological tests (e.g. coagulase) require a time-consuming (18-24h) culturing step. Based on the test results, rapid and strict hygiene rules, e.g. separation from non-infected persons, seem to be very effective to lower the spread of health-care associated MRSA. Here, we want to suggest an alternative strategy that can potentially facilitate the current diagnosis procedure.

The BaKillus S. aureus diagnosis tool: 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). A smear of a patient into a BaKillus-reporter culture could be enough to verify the presence of S. aureus within 0.5-2 hours (just limited by the time for BaKillus spore germination and reporter gene expression). This culture-independent detection could be precautionary used by patients of certain risk groups. The fast result would enable health-care institutions to directly start subsequent treatments/hygiene measures just after arrival of the patient and thus contact between infected and non-infected patients and therefore the spreading of multi-resistant pathogens could be lowered.

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.

Pathogen treatment tool:

Problem: ‘Inappropriate use of antimicrobials’ in humans is considered the ‘most important cause’ for antimicrobial resistance (AMR) emergence by the WHO. This includes both over and underuse. First, every use of antimicrobials puts the human microbiome under selective pressure, enhancing selectively the proliferation of resistant strains. Second, non-lethal quantities of an antimicrobial drug enables pathogens to develop resistance and prolongs the infection, giving resistant organisms increased possibility to spread

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, e.g. to treat chronic inflammation of the ENT tract. The approach’s main advantage is that the antibiotic production strictly depends on the QS of the pathogen. Antibiotics are just produced in the presence of an inflammation caused by a pathogen. Once the pathogen is killed, antibiotic production is down-regulated. By this means, the BaKillus strategy increases the efficiency of antimicrobial treatments and strongly reduces the mis- and overuse of antibiotics.

Table 2: Discussion of the BaKillus nasal spray.

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.

Typical time frame for the development of new drug applications [http://www.efpia.eu/uploads/Figures_2014_Final.pdf]

Distribution of costs for development of a new drug application[http://www.phrma.org/sites/default/files/pdf/2014_PhRMA_PROFILE.pdf]

Technomoral Scenario

Autonomous nano-exterminator

BaKillus actively detects and kills pathogenic bacteria. The first version, the BaKillus nasal spray, was an overall success about twenty years ago. It is still in use to treat all kind of bacterial surface infections, e.g. of the skin or nose. Now, a modified BaKillus version that can treat intracellular pathogens like M. tuberculosis went into clinical trials in the last months. But the week before, several test persons reported the same side effect and all participants were asked to stay in hospitals for several days. Two friends, one of whom participated in this study, are talking.

...You know, it is not about that I lost an opportunity to fund my studies or that I have to be in hospital the next days. I have this stuff in my body now. What hit them could also hit me!

Ah, you are exaggerating. What is it they have? They are feeling a craving for huge amounts of proteins. They simply go and a have their protein shake and they are fine. Such as you. You’ll be home by weekend and you can have your shake. They did a good job on the new BaKillus, I would prefer having milk shakes all the time, than dying of Tuberculosis.

Don’t try a trick on me, that’s not funny! We just don’t know what’s going on. Actually, most of the patients already lost their symptoms again. The other’s told me that they felt like not acting on their own. Really weird! And that’s the point. The doctors don’t know what it was or where it comes from. They just say BaKillus was perfectly designed not to interfere with the body system and they try to work out a solution. How can I still trust ‘em?

Oh, you have been to a company doctor? Better go to ask an independent doctor, they always have a different view.

No, I can’t. They barely have expertise because the company never release detailed information about products of this kind. Sure, you can read the patents, but I doubt that any outsider can really grasp what is going on there. I’m totally helpless. Can anybody help me? The thing is, that I have about a million BaKillus cells in my body system doing anything. I want them out!

Now I start to see your point. Remember my uncle, the old doctor and how he complained about the release of the BaKillus nasal spray twenty years ago? He never wanted to prescribe the BaKillus spray to people who had a middle ear inflammation. He said: Boy, you would never want to go on a plane without pilot, but you really want to put BaKillus in your nose? It is a complete black box to me, it doesn’t even tell me which infection you actually had!

Yeah, I remember! And we were always joking about him, saying that no one will need a doctor anymore with this new synthetic cells. Just go and get BaKillus, he will do the doctor’s work for you. Diagnosis and treatment within one shot of the spray. Did you know that the new BaKillus cells measure and react to more than dozens parameters of the body system? It is a data sampling monster, but a genius calculator allowing treatment with pinpoint accuracy! But God, the old man was right. With all those new nanotechnology stuff, you never know how it really functions. If only politicians would have slowed down this development.

Hum... but somehow it’s good that they didn’t. Just by the success of the first BaKillus leading to 60% less deaths by infectious diseases all around the world. Honestly, that was the only thing that was important to us until last week. And indeed, the government was a bit reserved in the first year of BaKillus. On the one hand, the discussion whether we want to use BaKillus or not was dominated by the critics of the Doctors Association talking about the risks of SynBio, their jobs, the black-box issue and insufficient consumer protection. On the other hand, NGOs and industry praised the all over availability and efficiency of BaKillus. But as the first patients were cured, all patients just wanted to use BaKillus and were convinced that BaKillus will lead us into the post-antibiotic era.

But over the years we seem to forget what BaKillus changed, now we see the bad side more pronounced. NGOs started to work on a moratorium of BaKillus. This morning an independent doctor came to see me. He is in a sort of ethics committee that is collaborating with a NGO and consumer protection organisations. They want our story to show the downside of BaKillus-like technologies. We demonstrate that even the developers don’t know what is going on.

Uh wow, guess they have their point there. Are you going to support them? How, do you feel about it?

Oh, I feel so stupid and I guess even those BaKillus cells are more clever than me. …