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The rise of antimicrobial resistance (AMR) is quickly rising to become one of humanity's most problematic health concerns.
The World Health Organization (WHO) indicates that AMR is on track to cause 10 million deaths by 2050 [1].
With significant fatalities forecasted to occur in Asia and Africa.
The root of the problem is that overuse of antimicrobial medicine over years and years has caused some strains of infectious bacteria to evolve and resist common antimicrobials.
Now, increased dosages are needed to combat these highly resistant bacteria.
Development into new antimicrobials is a valid solution to this problem.
Except that, this type of research is extremely costly.
As well as, there is no guarantee the bacteria will not evolve resistance.
Thus, negating all the time and resources spent creating the new antibiotic. However, a re-emerging technology can be a major part in the fight against AMR.
Bacteriophage technology was ignored by most western medicine for decades in favor of antibiotics.
Now, more and more research is being done into bacteriophage technology and new products are in development.
Our product aims to combat AMR bacteria at a cellular level.
We will take advantage of bacteriophage technology to introduce CRISPR-Cas proteins into virulent bacteria.
In the future, we hope to see comercial patients cured of illness using our product.
When confronted with a bacterial infection, nowadays, patients only have one choice, antibiotics.
With our proposed implementation, we expect to see bacteriophage-based therapy as common, easily accessible, and a possibly more effective therapy than antibiotics.
One integral component of our design is its versatility.
Natural phages are limited in use because of their intrinsic specificity.
For example, the T7 Bacteriophage normally only infects Escherichia coli bacteria.
If you don't have an E. coli infection, a normal T7 phage drug won't do anything.
Part of our project aims to remedy this problem.
Phages evolve to have tail fibers that are custom to the cell wall of their target bacteria.
Giving a phage different tail fibers will allow it to bind to the receptors on different bacterial receptors (Figure 1) [2].
Using a sortase-mediated reaction, we will attach nanobody proteins to phages for the creation of novel tail fibers [3].
What makes a sortase-mediated reaction perfect is its ability for easy editing of proteins.
One of the first tail fiber additions would be a common gram-negative surface receptor nanobody.
These and several other nanobodies corresponding to frequently expressed infectious bacterial surface receptors could be added on to phages and then mass produced as an over-the-counter drug.
On the other hand, with increasingly specific and resistant bacteria, we could engineer an individualized phage for that particular strain's surface receptors.
This is the area in which our product truly shines.
We see medical professionals taking the base product and adding what nanobodies they see fit for patient care.
The real-world realization is of one “super” phage that can be taken and modified for any bacterial infection.
Another crucial part of our product is what we are programming our bacteriophages to inject into bacteria.
Normally, phages will inject their whole genome into host bacteria.
The bacteria's ribosomes will then get “hijacked” and start coding proteins for the synthesis of new bacteriophages.
Once a sufficient amount of bacteriophages are synthesized in the host bacteria, the phages burst out of the cell, lysing the bacteria in the process [4].
However, our phages will be equipped with CRISPR-Cas13 proteins and the phage genome will be removed.
This accomplishes a design goal, decreasing the effects of AMR. First off, the CRISPR proteins will search the host bacteria's genome for antibiotic resistance transcripts.
Once the corresponding genes are found, the CRISPR proteins will then cut them out of the host genome.
We propose that this will make the host bacteria more susceptible to antibiotic medication; thus decreasing AMR.
In this case, the phage treatment will most likely have to be used in conjunction with an antibiotic, as these phages won't have the ability to lyse bacteria.
Of course, we expect to leave individual patient care decisions up to the primary care doctor.
Our main goal is to give people another option when it comes to pesky AMR bacterial infections.
Developing a drug fit for use in the human body is a long and arduous process.
The regulations set by the U.S. Food and Drug Administration (FDA) are strict and of the most extensive laws known [5].
We don't have the requisite experience to determine what possible flaws or regulations our design breaks and how it could harm the human body rather than support it.
That's why medical trials are a must for our product.
Design flaws would be investigated and thus worked out through the experiences at medical trials.
Phages have evolved to only target bacteria.
There is no chance of natural phages attacking human cells.
However, with the addition of new nanobodies onto the tail fibers, human cells might be able to be infected.
A solution for this would be to screen the nanobodies for human cell surface receptor compatibility.
For its intended purpose of infecting more bacterial cells, there should not be significant crossover between human cell surface receptors and bacterial cell surface receptors for the nanobodies.
The addition of the CRISPR-Cas proteins comes at a cost, the genome of the bacteriophage will not be included in the phage.
This means that the self-replicating properties of the bacteriophage are lost.
Human safety actually benefits from the loss of those properties.
As a mostly control free process, self-replication of foreign bodies in the human body is generally frowned upon.
On the other hand, labs must now use time and resources to engineer every single phage.
This situation is mostly ideal.
In that, product quality control is significantly easier to determine when each phage must be manufactured from scratch.
Additionally, limiting man-made phage replication in the human body is a major plus.
The absence of internal replication also benefits microbiome health.
If we set free a human-microbiome harming phage in the body.
It can only do so much before phage numbers get knocked down.
As well as, a body-positive phage, attacking infectious bacteria cells could evolve if given the chance and start targeting human cells.
In the end, our single-use bacteriophages have pros and cons.
Restricting phage replication makes for better stability and control.
However, a production problem is created. When taking this product and scaling up the commercial world.
One of the greatest challenges would be production efficiency and determining production methods.