The bacterium Streptococcus pneumoniae – which can cause pneumonia, meningitis, bacteremia and sepsis – likes to share its antibiotic-defeating weaponry with its neighbors. Individual cells can pass resistance genes to one another through a process called horizontal gene transfer, or by "transformation," the uptake of DNA from the environment.
Now researchers report that they can interrupt the cascade of cellular events that allows S. pneumoniae to swap or suck up DNA. The new findings, reported in the journal PLoS ONE, advance the effort to develop a reliable method for shutting down the spread of drug resistance in bacteria.
"Within the last few decades, S. pneumoniae has developed resistance to several classes of antibiotics," said University of Illinois pathobiology professor Gee Lau, who led the study. "Importantly, it has been shown that antibiotic stress – the use of antibiotics to treat an infection – can actually induce the transfer of resistance genes among S. pneumoniae. Our approach inhibits resistance gene transfer in all strains of S. pneumoniae, and does so without increasing selective pressure and without increasing the likelihood that resistant strains will become dominant."
Lau and his colleagues focused on blocking a protein that, when it binds to a receptor in the bacterial cell membrane, spurs a series of events in the cell that makes the bacterium "competent" to receive new genetic material. The researchers hypothesized that interfering with this protein (called CSP) would hinder its ability to promote gene transfer.
In previous work published late last year in the journal PLoS Pathogens, Lau's team identified proteins that could be made in the lab that were structurally very similar to the CSP proteins. These artificial CSPs can dock with the membrane receptors, block the bacterial CSPs' access to the receptors and reduce bacterial competence, as well as reducing the infectious capacity of S. pneumoniae.
In the new study, the researchers fine-tuned the amino acid structure of more than a dozen artificial CSPs and tested how well they inhibited the S. pneumoniae CSPs. They also tested their ability (or, more desirably, their inability) to mimic the activity of CSPs in bacterial cells.
"The chemical properties of individual amino acids in a protein can greatly influence the protein's activity," Lau said.
The team identified several artificial CSPs that both inhibited the bacterial CSPs and reduced S. pneumoniae competence by more than 90 percent.
"This strategy will likely help us reduce the spread of antibiotic-resistance genes among S. pneumoniae and perhaps other species of streptococcus bacteria," Lau said.
Paper: "Saturated Alanine Scanning Mutagenesis of the Pneumococcus Competence Stimulating Peptide Identifies Analogs That Inhibit Genetic Transformation." PLoS ONE
University of Illinois at Urbana-Champaign: http://www.uiuc.edu
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Rising temperatures and a more acidic ocean may spell trouble for the Chesapeake Bay's iconic crabs, oysters and fish
Huge specimen caught in Antarctic waters by New Zealand fishing crew is one of few ever examined
Lonesome George, the worlds most famous tortoise, goes on display at the American Museum of Natural History.
Oxytricha trifallax lives in ponds all over the world. Under an electron microscope it looks like a football adorned with tassels. The tiny fringes are the cilia it uses to move around and gobble up algae. What makes Oxytricha unusual, however, is the crazy things it does with its DNA.
A Japanese woman with macular degeneration is the first person to be treated with induced pluripotent stem cells, made from her own skin
A DNA sequencer the size of a cell phone could change where, and how, gene research occurs.One day in 1989, biophysicist David Deamer pulled his car off California’s Interstate 5 to hurriedly scribble down an idea. In a mental flash, he had pictured a strand of DNA threading its way through a microscopic pore. Grabbing a pen and a yellow pad, he sketched out a radical new way to study the molecule of life.
New research led by the University of Leicester in the U.K. gives a blow-by-blow account of the injuries inflicted on King Richard III at the Battle of Bosworth Field on Aug 22, 1485. Modern forensic analysis of the King’s skeletal remains reveals that three of his injuries had the potential to cause death quickly.
Look into the jaws of a Mosasaurus and you will gaze into a nightmare.
Although it's far from the sort of brain transplant beloved by science fiction enthusiasts, scientists have taken one step in that direction: they have spliced a key human brain gene into mice.
A network in the brain that helps control daydreaming seem to be slower to develop in children with attention deficit hyperactivity disorder.