Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Common bacteria on verge of becoming antibiotic-resistant superbugs

26.03.2015

Antibiotic resistance is poised to spread globally among bacteria frequently implicated in respiratory and urinary infections in hospital settings, according to new research at Washington University School of Medicine in St. Louis.

The study shows that two genes that confer resistance against a particularly strong class of antibiotics can be shared easily among a family of bacteria responsible for a significant portion of hospital-associated infections.


Bacteria that cause many hospital-associated infections are ready to quickly share genes that allow them to resist powerful antibiotics. The illustration, based on electron micrographs and created by the Centers for Disease Control and Prevention, shows one of these antibiotic-resistant bacteria.

Credit: CDC/James Archer

Drug-resistant germs in the same family of bacteria recently infected several patients at two Los Angeles hospitals. The infections have been linked to medical scopes believed to have been contaminated with bacteria that can resist carbapenems, potent antibiotics that are supposed to be used only in gravely ill patients or those infected by resistant bacteria.

"Carbapenems are one of our last resorts for treating bacterial infections, what we use when nothing else works," said senior author Gautam Dantas, PhD, associate professor of pathology and immunology. "Given what we know now, I don't think it's overstating the case to say that for certain types of infections, we may be looking at the start of the post-antibiotic era, a time when most of the antibiotics we rely on to treat bacterial infections are no longer effective."

Dantas and other experts recommend strictly limiting the usage of carbapenems to cases in which no other treatments can help.

The study, conducted by researchers at Washington University, Barnes-Jewish Hospital and the National University of Sciences and Technology in Pakistan, is available online in Emerging Infectious Diseases.

The researchers studied a family of bacteria called Enterobacteriaceae, which includes E. coli, Klebsiella pneumoniae and Enterobacter. Some strains of these bacteria do not cause illness and can help keep the body healthy. But in people with weakened immune systems, infections with carbapenem-resistant versions of these bacteria can be deadly.

The Centers for Disease Control and Prevention named carbapenem-resistant Enterobacteriaceae as one of the three most urgent threats among emerging forms of antibiotic-resistant disease. Studies have shown the fatality rate for these infections is above 50 percent in patients with weakened immune systems.

Two genes are primarily responsible for carbapenem-resistant versions of these disease-causing bacteria. One gene, KPC, was detected in New York in 2001 and quickly spread around most of the world, with the exception of India, Pakistan and other South Asian countries. This gene was present in the bacteria that recently contaminated medical equipment in a Los Angeles hospital where two patients died.

A second carbapenem resistance gene, NDM-1, was identified in 2006 in New Delhi, India. It was soon detected throughout South Asia, and most patients infected by bacteria with NDM-1 have had an epidemiological link to South Asian countries.

Dantas and his collaborators were curious about why the two resistance genes seemed to be geographically exclusive. For the study, they compared the genomes of carbapenem-resistant bacteria isolated in the United States with those of carbapenem-resistant bacteria isolated in Pakistan.

Based on the apparent geographic exclusivity of the two resistance genes, the scientists expected to find that bacteria from the two regions were genetically different. Such differences could explain why the two resistance genes weren't intermingling. But the researchers' results showed otherwise. The bacteria's high genetic similarity suggests that the antibiotic resistance genes could be shared easily between bacteria from the two geographic regions.

The researchers also sequenced a special portion of bacterial genetic material called plasmids. Most of a bacteria's DNA is found in its chromosome, but bacteria also have many extra, smaller and circular bits of DNA known as plasmids that easily can pass from one bacterial strain to another. A plasmid is like a bacterial gene delivery truck; it is the primary way antibiotic resistance genes spread between bacteria.

The researchers identified a few key instances in which the plasmids carrying NDM-1 or KPC were nearly identical, meaning they easily could facilitate the spread of antibiotic resistance between disease-causing bacteria found in the United States and South Asia. Recent evidence suggests that this intermingling already may be happening in parts of China.

"Our findings also suggest it's going to get easier for strains of these bacteria that are not yet resistant to pick up a gene that lets them survive carbapenem treatment," Dantas said. "Typically, that's not going to be a problem for most of us, but as drug-resistant forms of Enterobacteriaceae become more widespread, the odds will increase that we'll pass one of these superbugs on to a friend with a weakened immune system who can really be hurt by them."

###

This research was supported by the National Institutes of Health (NIH) Director's New Innovator Award, the National Institute of Diabetes and Digestive and Kidney Diseases, and the National Institute of General Medical Sciences, grant numbers DP2DK098089 and R01GM099538.

Pesesky MW, Hussain T, Wallace M, Wang B, Andleeb S, Burnham C-AD, Dantas G. KPC and NDM-1 are harbored by related Enterobacteriaceae strains and plasmid backbones form distinct geographies. Emerging Infectious Diseases, June 2015; http://dx.doi.org/10.3201/eid2106.141504.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient-care institutions in the nation, currently ranked sixth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.

Media Contact

Michael C. Purdy
purdym@wustl.edu
314-286-0122

 @WUSTLmed

http://www.medicine.wustl.edu 

Michael C. Purdy | EurekAlert!

More articles from Life Sciences:

nachricht Water world
20.11.2017 | Washington University in St. Louis

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

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...

Im Focus: Visual intelligence is not the same as IQ

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...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>