Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Antibiotic-eating bug unearthed in soil

07.12.2012
A newly discovered bacterium degrades an antibiotic both to protect itself and get nutrition
It’s well known how bacteria exposed to antibiotics for long periods will find ways to resist the drugs—by quickly pumping them out of their cells, for instance, or modifying the compounds so they’re no longer toxic.

Now new research has uncovered another possible mechanism of antibiotic “resistance” in soil. In a paper publishing this week in the Journal of Environmental Quality, a group of Canadian and French scientists report on a soil bacterium that breaks down the common veterinary antibiotic, sulfamethazine, and uses it for growth.

Certain soil bacteria are already known to live off, or “eat,” agricultural pesticides and herbicides, says the study’s leader, Ed Topp, a soil microbiologist with Agriculture and Agri-Food Canada in London, Ontario. In fact, the microbes’ presence in farm fields can cause these agrichemicals to fail.

But to Topp’s knowledge, this is the first report of a soil microorganism that degrades an antibiotic both to protect itself and get nutrition.

“I think it’s kind of a game changer in terms of how we think about our environment and antibiotic resistance,” he says.

Concerns about widespread antibiotic resistance are what led Topp and his collaborators to set up an experiment 14 years ago, in which they dosed soils annually with environmentally relevant concentrations of three veterinary antibiotics: sulfamethazine, tylosin, and chlortetracycline. Commonly fed to pigs and other livestock, antibiotics are thought to keep animals healthier. But they’re also excreted in manure, which is then spread once a year as fertilizer in countless North American farm fields.

The researchers first wanted to know whether these yearly applications were promoting higher levels of antibiotic resistance in soil bacteria. But a few years ago, they also decided to compare the persistence of the drugs in soil plots that had been repeatedly dosed, versus fresh soils where antibiotics were never applied.

They did this experiment, Topp explains, because of previous work indicating that pesticides often break down more quickly in soils with a long history of exposure, indicating that pesticide-degrading microbes have been selected for over time.

Still, it came as a surprise when they saw antibiotics also degrading much faster in long-term, treated plots than in fresh, control soils, he says. In particular, sulfamethazine—a member of the antibiotic class called sulfonamides—disappeared up to five times faster.

The researchers subsequently cultured from the treated plots a new strain of Microbacterium, an actinomycete that uses sulfamethazine as a nitrogen and carbon source. Extremely common in soil, actinomycete bacteria are known to degrade a wide range of organic compounds. And now at least two other sulfanomide-degrading Microbacterium strains have been reported, Topp says: one from soil and another from a sewage treatment plant.

Taken together, the findings suggest that the capability to break down sulfanomides could be widespread. And if it’s indeed true that “the microbiology in the environment is learning to break these drugs down more rapidly when exposed to them, this would effectively reduce the amount of time that the environment is exposed to these drugs and therefore possibly attenuate the impacts,” Topp says.

Not that negative impacts aren’t still occurring, he cautions. In particular, long-term exposure to antibiotics puts significant pressure on soil bacteria to evolve resistance, which they typically do by giving and receiving genes that let them detoxify drugs, or keep the compounds out of their cells.

What the new research suggests, though, is that soil bacteria could be swapping genes for breaking down antibiotics at the same time.

“My guess is that’s probably what’s happening, but it remains to be determined,” Topp says. “It’s actually extremely fascinating.”

The work was funded by Agriculture and Agri-Food Canada.

The full article is available for no charge for 30 days following the date of this summary. View the abstract at https://dl.sciencesocieties.org/publications/jeq/abstracts/0/0/jeq2012.0162.

The Journal of Environmental Quality is a peer-reviewed, international journal of environmental quality in natural and agricultural ecosystems published six times a year by the American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and the Soil Science Society of America (SSSA). The Journal of Environmental Quality covers various aspects of anthropogenic impacts on the environment, including terrestrial, atmospheric, and aquatic systems.

The American Society of Agronomy (ASA) www.agronomy.org, is a scientific society helping its 8,000+ members advance the disciplines and practices of agronomy by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.

Madeline Fisher | EurekAlert!
Further information:
http://www.agronomy.org/

More articles from Agricultural and Forestry Science:

nachricht Open-access article on Mexican bean beetles offers control tips
03.02.2016 | Entomological Society of America

nachricht Improved harvest for small farms thanks to naturally cloned crops
29.01.2016 | Universität Zürich

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Production of an AIDS vaccine in algae

Today, plants and microorganisms are heavily used for the production of medicinal products. The production of biopharmaceuticals in plants, also referred to as “Molecular Pharming”, represents a continuously growing field of plant biotechnology. Preferred host organisms include yeast and crop plants, such as maize and potato – plants with high demands. With the help of a special algal strain, the research team of Prof. Ralph Bock at the Max Planck Institute of Molecular Plant Physiology in Potsdam strives to develop a more efficient and resource-saving system for the production of medicines and vaccines. They tested its practicality by synthesizing a component of a potential AIDS vaccine.

The use of plants and microorganisms to produce pharmaceuticals is nothing new. In 1982, bacteria were genetically modified to produce human insulin, a drug...

Im Focus: The most accurate optical single-ion clock worldwide

Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock which attains an accuracy which had only been predicted theoretically so far. Their optical ytterbium clock achieved a relative systematic measurement uncertainty of 3 E-18. The results have been published in the current issue of the scientific journal "Physical Review Letters".

Atomic clock experts from the Physikalisch-Technische Bundesanstalt (PTB) are the first research group in the world to have built an optical single-ion clock...

Im Focus: Goodbye ground control: autonomous nanosatellites

The University of Würzburg has two new space projects in the pipeline which are concerned with the observation of planets and autonomous fault correction aboard satellites. The German Federal Ministry of Economic Affairs and Energy funds the projects with around 1.6 million euros.

Detecting tornadoes that sweep across Mars. Discovering meteors that fall to Earth. Investigating strange lightning that flashes from Earth's atmosphere into...

Im Focus: Flow phenomena on solid surfaces: Physicists highlight key role played by boundary layer velocity

Physicists from Saarland University and the ESPCI in Paris have shown how liquids on solid surfaces can be made to slide over the surface a bit like a bobsleigh on ice. The key is to apply a coating at the boundary between the liquid and the surface that induces the liquid to slip. This results in an increase in the average flow velocity of the liquid and its throughput. This was demonstrated by studying the behaviour of droplets on surfaces with different coatings as they evolved into the equilibrium state. The results could prove useful in optimizing industrial processes, such as the extrusion of plastics.

The study has been published in the respected academic journal PNAS (Proceedings of the National Academy of Sciences of the United States of America).

Im Focus: New study: How stable is the West Antarctic Ice Sheet?

Exceeding critical temperature limits in the Southern Ocean may cause the collapse of ice sheets and a sharp rise in sea levels

A future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Travel grants available: Meet the world’s most proficient mathematicians and computer scientists

09.02.2016 | Event News

AKL’16: Experience Laser Technology Live in Europe´s Largest Laser Application Center!

02.02.2016 | Event News

From intelligent knee braces to anti-theft backpacks

26.01.2016 | Event News

 
Latest News

Fish fins can sense touch

11.02.2016 | Life Sciences

New paths for generation of ultracold molecules

11.02.2016 | Physics and Astronomy

Southwest sliding into a drier climate

11.02.2016 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>