. Energy News .

Antibiotic-eating bug unearthed in soil
by Staff Writers
Madison, WI (SPX) Dec 12, 2012

The researchers did this experiment 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.

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 published 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. abstract at https://dl.sciencesocieties.org/publications/jeq/abstracts/0/0/jeq2012.0162.


Related Links
American Society of Agronomy
Farming Today - Suppliers and Technology

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

Get Our Free Newsletters
Space - Defense - Environment - Energy - Solar - Nuclear


Quantifying corn rootworm damage
Urbana IL (SPX) Dec 12, 2012
Every year farmers spend a lot of money trying to control corn rootworm larvae, which are a significant threat to maize production in the United States and, more recently, in Europe. University of Illinois researchers have been working on validating a model for estimating damage functions. Nicholas Tinsley, a doctoral candidate in crop sciences, has refined a model developed in 2009 by res ... read more

Google Maps returns to iPhone after Apple fiasco

NASA-NOAA Satellite Reveals New Views of Earth at Night

Skybox Imaging Completes Significant Testing Milestone Preceding its First Satellite and Product Launch

First-ever hyperspectral images of Earth's auroras

Third Boeing GPS IIF Begins Operation After Early Handover to USAF

Putin Urges CIS Countries to Join Glonass

Third Galileo satellite begins transmitting navigation signal

Retired GIOVE-A satellite helps SSTL demonstrate first High Altitude GPS navigation fix

As Amazon urbanizes, rural fires burn unchecked

Global drive in support of Brazil's threatened Awa tribe

World's biggest, oldest trees are dying: research

'Come out of the forest' to save the trees

Can Algae-Derived Oils Support Large-Scale, Low-Cost Biofuels Production?

Plastic packaging industry is moving towards completely bio-based products

Gases from Grasses

Garbage bug may help lower the cost of biofuel

Asian Supermarket Distribution Center Completes Solar Installation

KYOCERA Solar Panels Power Innovative Solar-to-EV Project with Smart City San Diego at San Diego Zoo

Solar Energy Solidarity to donate over 60kW to PV projects

Solar power prices to continue falling through 2025

Ground broken on Irish Midlands wind farm

GE, MetLife and Union Bank Invest in Kansas Wind Farm

Wind speeds in southern New England declining inland, remaining steady on coast

Brazil advances wind power development

China mine blast kills 17: state media

China mine blast toll rises to 23

China mine blast kills 18: state media

US shale gas drives up coal exports

Top China provincial leader sacked: Xinhua

China gives hijackers death sentences

US lawmakers, Chinese friends seek Liu Xiaobo release

Two Tibetans die in latest self-immolations

The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement