The study not only reveals multiple, new drug targets for this human infection, it also suggests that the typical methods of studying bacteria in rich laboratory media may not be the best way to identify much-needed antimicrobial drug targets.
The paper (http://mbio.asm.org/content/3/4/e00113-12) focuses on a Gram-negative bacteria called A. baumanni. It is published in the current issue of mBio, as an 'editor's choice' paper. The findings may be relevant to other Gram-negative bacteria as well.
A. baumannii is responsible for a growing number of hospital-acquired infections around the world. It can be fatal to patients with serious illnesses, the elderly and those who have had surgeries. Infections also have been seen in soldiers returning from Iraq and Afghanistan with battlefield injuries.
"Generally, healthy people don't get infected," explains lead author Timothy C. Umland, PhD, research scientist at Hauptman-Woodward Medical Research Institute (HWI) and professor of structural biology in the University at Buffalo School of Medicine and Biomedical Sciences. "But what's challenging about A. baumannii is that it can survive in the hospital environment and is very hard to eradicate with common disinfectants, leading to healthcare-associated infections."
Typically, the way that essential genes for microbial pathogens are found is by growing the bacteria under optimal conditions, says co-author Thomas A. Russo, MD, professor in the UB departments of medicine and microbiology and immunology. Genes found to be essential for growth are then entered into the Database of Essential Genes (DEG), which contains genes considered essential for the sustenance of each organism.
The researchers at HWI and UB decided to try to better understand what A. baumannii needs in order to grow when infecting patients.
"Laboratory conditions create a different type of environment from what happens in patients," Umland says, "where certain nutrients the bacteria need will be present in very low amounts and where the bacteria encounter immune and inflammatory responses. We were purposely trying to test for genes that are important for growth in these more realistic environments."
The team performed a genetic screen designed to identify bacterial genes absolutely required for the growth and survival of A. baumannii in human ascites, a peritoneal fluid that accumulates under a variety of pathologic conditions.
"We found that nearly all of these 18 genes had not been identified as essential in the DEG because they weren't necessary for growth in an ideal laboratory environment," explains Russo. "This is a large set of genes that has been flying under the radar."
He adds: "The biggest concern is that quite a few strains of A. baumannii are resistant to nearly all anti-microbial drugs and some strains are resistant to all of them. To make things worse, there are no new agents being tested for human use in the drug pipeline that are active against A. baumannii. This is a huge problem."
Not only do the new genes suggest brand new, high-value drug targets for A. baumannii infections, but the genes that have been identified may be relevant to other Gram-negative infections.
"So far, our computational models show that these genes seem to be conserved across Gram-negative infections, meaning that they may lead to new drugs that would be effective for other drug-resistant infections as well," says Umland.
The researchers who collaborated on the study are now pursuing antibacterial drug discovery efforts focused on the newly identified bacterial targets.
The research was funded by grants from the Telemedicine and Advance Technical Research Center of the U.S. Army Medical Research and Materiel Command, an interdisciplinary grant from UB and a VA Merit Review grant from the U.S. Department of Veterans Affairs.
Other co-authors are: L. Wayne Schultz, PhD, of HWI and UB, and Ulrike MacDonald, Janet M. Beanan and Ruth Olson of the UB Department of Medicine, the Department of Microbiology and Immunology and UB's Witebsky Center for Microbial Pathogenesis.
Ellen Goldbaum | EurekAlert!
Ambush in a petri dish
24.11.2017 | Friedrich-Schiller-Universität Jena
Meadows beat out shrubs when it comes to storing carbon
23.11.2017 | Norwegian University of Science and Technology
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
24.11.2017 | Physics and Astronomy
24.11.2017 | Health and Medicine
24.11.2017 | Earth Sciences