In the past decade, scientists were baffled with the growing number of bacteria, which developed resistance to the common and sometimes high end antibiotics used to treat such infections. Although methicillin resistance among Staphylococcus aureus (MRSA) was first detected in the year 1961, there were novel strains of bacteria emerging in the past decade which has gone further to become ‘multi drug resistance’ and ‘hyper virulent’. According to scientists, these strains have surpassed HIV/AIDS as the biggest killer in the United States and continue to cause havoc in the health care system each year.
Is there an antibiotic that can answer the problem of MRSA?
In a recent article titled “Small Molecule Inhibitors of Staphylococcus aureus RnpA Alter Cellular mRNA Turnover, Exhibit Antimicrobial Activity, and Attenuate Pathogenesis” published in pathogens, there is a way to access the vital cellular mechanisms of antibiotic resistance Staphylococcus aureus (Staph aureus) and thereby inhibit its growth. It is considered a breakthrough research and could lead towards developing a method to counteract the emerging problem of drug resistance.
According to Dr Dunman at the University of Rochester Medical Center, New York, whom was the lead person in this novel approach, “This was a great starting point” and many avenues are now open for scientists to explore the most efficient way to utilize this technology in developing a commercial antibiotic.
What are the strategies used for developing antibiotics?
The difference in the research lead by Dr Dunman in comparison to other research teams embarking on finding a solution for methicillin resistance, was their approach. While many of the other teams looked towards blocking the bacterial transcribing process of RNA or the conversion of RNA into proteins, Dr Dunmans research team looked towards degradation as a possible alternative. Although the concept was present for many years, none was able to make a breakthrough in developing or finding a substance which can actually interfere with the process, in a meaningful way.
How RNA degradation can be used for antimicrobial activity?
RNA degradation is an essential process for any living cell, as it would eliminate unused transcripts. If the degradation process do not function, these unneeded RNA transcripts would accumulate and would soon lead to ‘cellular chaos’ which will destroy the cell, and in this case, the Staphylococcus aureus bacteria. However, the complex nature of the process made it difficult for researchers to come up with a substance that acts on bacterial enzymes, which facilitate RNA degradation. Dr Dunman and the researchers at the University of Rochester Medical Center, New York discovered a protein (RnpA) which catalyze the degradation of r-RNA and m-RNA in Staph aureus in vitro. Furthermore, they were also successful in discovering a substance (a molecule), which would inhibit the activity of RnpA, and its high affinity towards MRSA bacteria and other drug resistant bacteria would make the substance act as a antibacterial agent.
In a test trial, the researchers were able to improve the survival of more than 50% of systemic mouse infection models, which proved its effectiveness against MRSA bacteria.
How soon would the new antibiotic be available for the public?
However, Dr Dunman and his researcher team is of the view that, there are two types of Staphylococcus aureus present in these mouse models and they are the ones which responds to the RNA degradation disrupting molecule and the ones who does not respond to the same. At the same time, this substance in its present state have shown to be toxic to some of the other human cells and may cause more harm than good if used in human models. Therefore, it will be some time before the human kind sees a new type of antibiotic, which would be effective against the ever-dangerous drug resistance substrates of Staphylococcus aureus.
Olson, P.D., et al. "Small molecule inhibitors of Staphylococcus aureus RnpA alter cellular mRNA turnover, exhibit antimicrobial activity, and attenuate pathogenesis." PLoS Pathogens. http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1001287
National Institute of Allergy and Infectious Diseases - Antimicrobial (Drug) Resistance - http://www.niaid.nih.gov/topics/antimicrobialResistance/Examples/mrsa/Pages/overview.aspx
National Institute of Health - New Approach to Fighting Staph Infections - http://www.nih.gov/researchmatters/february2011/02282011staph.htm