Antibiotic Resistant Disease
Researchers at Lawrence Livermore National Laboratory (LLNL) have discovered a new way to combat antibiotic resistant bacteria by using the bacteria's own genes. For more than 50 years, antibiotics have been used to treat a variety of deadly infections and saved countless lives. Its broad introduction and application has changed the face of medicine and world populations worldwide. Yet, despite the advances made to antibiotics over the years, the list of antibiotic resistant bacteria, such as MRSA (Methicillin-resistant Staphylococcus aureus), E.coli, Salmonella and Campylobacter, is growing and becoming one of the world's most serious health concerns. Infections once routinely treatable have now become more difficult to control as well as lethal in some cases.
Although TAPH has been causing infections probably as long as the human race has existed, MRSA has a relatively short history. MRSA was first noted in 1961, about two years after the antibiotic methicillin was initially used to treat staph and other infectious bacteria. The resistance to methicillin was due to a penicillin-binding protein coded for by a mobile genetic element termed the methicillin-resistant gene. In recent years, the gene has continued to evolve so that many MRSA strains are currently resistant to several different antibiotics such as penicillin, oxacillin, and amoxicillin.
That's where Paul Jackson and his Livermore team come in. The group has taken a new approach to combating antibiotic resistant bacteria by developing a new generation of antibiotics, based upon a much deeper understanding of the bacteria's own genes. The method consists of turning the pathogens' own genes and processes against it.
"Rather than looking for a more traditional solution to the problem and perhaps finding a chemical or antimicrobial solution, we decided to harness genetic sequencing and take a closer look at the makeup of the pathogen's DNA," Jackson said. "In doing so, we've identified the genes within bacteria that encode for lytic proteins -- a very important component for cell survival and one that we could leverage against it."
Lytic proteins are used by bacteria to make small nicks at strategic points within the cell wall so the cell can synthesize new cell wall and divide.
With the lytic protein-producing genes indentified, Jackson's team used the genes to drive synthesis of the encoded proteins in the laboratory and purified them. They then introduced the purified protein to the exterior of the bacterial cells. The results were quick and very clear -- complete and total destruction of the pathogen's cell wall. Because these lytic proteins are unique to each bacterial species, the purified protein will only target that specific bacteria cell species, leaving other cells unharmed.
Because these proteins are essential to the life cycle of the cell, it is unlikely that the bacteria could adequately defend against it. If it tried, it would likely deprive the cell of the ability to divide -- a process absolutely required for production of more pathogen cells.
For the moment, traditional treatment methods still includes certain specific antibiotics (for example, vancomycin [Vancocin], linezolid [Zyvox], and others, often in combination with vancomycin). Most moderate to severe infections need to be treated by intravenous antibiotics.
For further information: https://www.llnl.gov/news/newsreleases/2011/Jan/NR-10-11-01-05.html