Methicillin-resistant Staphylococcus aureus (MRSA) has become an powerful adversary for many health institutions around the world, ever since Alexander Flemming fortuitously discovered penicillin.
Bacteria’s ability to mutate, reproduce quickly and share genetic information between species and even across species has lead to the rise of a whole new group of organisms. This group has been popularized by the media as “superbugs,” yet this is despite the fact that bacteria and actual bugs are completely different creatures.
In the UK, 690 cases of MRSA were reported last year, with the United States reporting well over 278,000 cases and 19,000 deaths due to the drug resistant bacteria.
The fact that bacteria can reproduce asexually, that is without the need for another individual, has contributed to the increase in antibiotic-resistant strains. Variation in genetic sequences within a bacterial population means that some organisms possess genes capable of procuring a resistance to the drugs normally prescribed to patients.
Even if almost all bacteria is eliminated yet one individual survives, that one individual now carries the genetic information for resistance, a particularly valuable trait in an antibiotic rich environment such as hospitals. As a result, one bacteria soon becomes two, and two become four, allowing a rapid spread of the resistant genes in this new population.
Currently, there are a handful of known drugs that are effective against these pathogens, such as bactrim and vancomycin, however, resistance to these compounds has also been discovered.
Despite this, new research has discovered a novel way of treating antibiotic-resistant bacteria thanks to a computer.
Specialists from the departments of Chemistry and Biochemistry, the Freimann Life Sciences Center and the Department of Biological Sciences at the University of Notre Dame, in Indiana, USA, have discovered a whole new class of antibiotics that could be used to treat these types of infections.
The work was published in the Journal of the American Chemical Society.
Using a highly specialized computer, the research team analyzed over 1.2 million different compounds, and found a new class that are dubbed oxadiazoles, and look extremely promising for the treatment of MRSA infections.
Oxadiazoles have the ability to inhibit a structure known as penicillin-binding protein (PBP2a). Typically, these PBP proteins are involved in the later stages of cell wall formation in bacteria, which is essential to the organism as it promotes healthy growth and reproduction.
In normal bacteria, several antibiotics like penicillin target these PBPs, meaning the bacterial cell wall becomes compromised.
However, genes in species like MRSA produce a variant, PBP2a, that has a low affinity to drugs like penicillin or methicillin.
Yet the chemical structure of the oxadiazoles allows the drug to inhibit the formation of the PBP2a, altering the cell wall and resulting in an organism that can be once again targeted by other drugs.
Importantly, the way that this drug is taken also makes it stand out from the crowd. Treatment for MRSA related conditions are usually given intravenously, however the oxadiazoles are just as effective when taken orally.
Finding a way to counter MRSA has been a Holy Grail for years for many scientists, and the work by the team has received its well-deserved attention.
Speaking to Gene Stowe and Marissa Gebhard for the University of Notre Dame news release, the Dean of the College of Science Greg Crawford was quick to praise the work of lead authors Mayland Chang and Shahriar Mobashery: “[their] discovery of a class of compounds that combat drug resistant bacteria such as MRSA could save thousands of lives around the world. We are grateful for their leadership and persistence in fighting drug resistance.
For what other applications could computer screening be used in medical sciences?