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The discovery of the first antibiotic in 1928 revolutionized the medical field and many subsequent years of research [1].
Naturally, mass production and overuse followed the successful exploitation of such findings.
The popularity of antibiotics grew exponentially, and they eventually made it past pharmaceuticals and into the food industry and agriculture.
By the late 1900's, antibiotic resistance became a major concern.
In 2019 alone, almost 5 million deaths worldwide were a result of antimicrobial resistance, and the numbers continue to grow [2].
Many current initiatives are focused on prevention and awareness as well as the continuous endeavor to find new antibiotics while the inevitable consequences of antibiotic resistance remain untreated.
Our project aims to harness the power of synthetic biology to combat pathogens with a mechanism of their own: Sortase A.
An enzyme used by many pathogenic bacteria to customize surface proteins in order to adhere to epithelial lining and mucosal cells of their host and ultimately cause disease [3].
Inspired by the promising results of Hess, et al.'s research on modification of phage surface proteins, our project utilizes Sortase A to achieve expansion of host range for phage therapy.
Sortase A catalyzes peptide ligation at a specific sequence (LPXTG) which allows for accurate and efficient customization of the phage tail fiber.
While other techniques like tail fiber mutagenesis have proven effective in expanding host range, it requires a deep understanding of phage genome, viral surface proteins, and significant insight into the relationship between a protein genetic sequence and its function which limits the capacity for diversifying functionality of phage proteins.
Existing research involving pathogenic bacterial cell receptors and their interaction with bacteriophages significantly enhances our ability to use a wide range of tail fiber proteins to target various cell receptors with the goal of avoiding the development of phage resistance.
We predict that treatment with a cocktail of a variety of engineered bacteriophages would bypass the selection against a specific bacterial receptor, making the treatment more effective [4].
Safety has been a profound obstacle to the success of clinical use of phage therapy in humans.
This concern arises from the inability to target pathogenic bacteria selectively and exclusively in a human body while avoiding healthy human cells as well as our commensal microbiome, making CRISPR Cas13a an attractive method for specific gene targeting [5].
Similarly inspired by the work of Kiga et al, we exploited Cas13a's promiscuous ssRNA cleavage to target two antibiotic resistance genes: tetracycline and carbapenem [6].
By targeting the transcriptome, we add a layer of differential targeting for bacteria expressing the antibiotic resistance gene regardless of its origin (genomic or plasmid-borne).
In addition to disarming the bacteria's defenses against the selected antibiotic, the promiscuous cleavage activity inhibits growth and, in some cases, kills the bacteria which allows the resistance gene to act as a marker for further selection.
We focused our outreach efforts on spreading awareness on antibiotic resistance among the general public as well as influential professionals such as doctors and pharmacists.
We strive to educate the public on the fatality of this growing problem since it is often overlooked in the grand scheme of things.
We presented to younger age groups about the diversity of microorganisms around them and how synthetic biology tools and technologies can be used to address health problems.
We also shared our project and results with other labs and colleagues at our knowledge to their future careers.
We hope that our efforts will motivate youths to develop an interest in the topic and carry their knowledge to their future careers.
We also hope that by sharing our project with a professional audience, they will choose to take charge in combating antibiotic resistance to truly make a difference.
We also encourage our audience to consult medical professionals more regularly and follow their guidance.