Skip to Main Content

Latest News

Advertisement
Advertise Here
November 19, 2010
DOI: 10.1021/CEN111610144818

Turning Up The Heat On Antibiotic Resistant Bacteria

Wastewater Treatment: High temperatures reduce the load of antibiotic resistance genes

Laura Cassiday

Shutterstock
DIGESTIVE AID By increasing the temperature at which bacteria digest wastewater solids in anaerobic tanks like these, scientists could slow the spread of antibiotic resistance.
  • Print this article
  • Email the editor

Latest News



October 28, 2011

Speedy Homemade-Explosive Detector

Forensic Chemistry: A new method could increase the number of explosives detected by airport screeners.

Solar Panel Makers Cry Foul

Trade: U.S. companies complain of market dumping by China.

Novartis To Cut 2,000 Jobs

Layoffs follow similar moves by Amgen, AstraZeneca.

Nations Break Impasse On Waste

Environment: Ban to halt export of hazardous waste to developing world.

New Leader For Lawrence Livermore

Penrose (Parney) Albright will direct DOE national lab.

Hair Reveals Source Of People's Exposure To Mercury

Toxic Exposure: Mercury isotopes in human hair illuminate dietary and industrial sources.

Why The Long Fat?

Cancer Biochemistry: Mass spectrometry follows the metabolism of very long fatty acids in cancer cells.

Text Size A A

Bacteria are evolving resistance to antibiotics at an alarming rate, fueled by decades of overuse of the drugs in medicine and agriculture. Now researchers have developed a method that could slow the spread of resistance genes in the environment by reducing their release through treated sewage (Environ. Sci. Technol., DOI: 10.1021/es102765a).

When people take antibiotics, they can excrete resistant bacteria from their guts and flush them into the sewer system. The wastewater and associated solids then travel to a treatment plant. Farmers often apply treated wastewater solids, known as sewage sludge, to their fields as fertilizer. Bacteria in the sludge can share antibiotic resistance genes with other microbes in the environment. Yet according to Timothy LaPara, an environmental engineer at the University of Minnesota, Twin Cities, scientists lack a good method to remove antibiotic resistant bacteria during sewage treatment.

Most treatment plants incubate sludge in "digester" tanks at 37°C, where sewage bacteria decompose organic material and destroy pathogens, including other bacteria. Two types of digesters – aerobic digesters with added oxygen, and anaerobic without – select for different populations of bacteria.

"A lot of these digesters are operated at our body temperature, which actually is a very good condition for resistant bacteria to survive," says LaPara.

So he and colleague David Diehl examined how temperature affected the quantities of resistance genes in bacterial populations within digesters. They studied five bacterial genes encoding tetracycline resistance and one gene encoding the integrase of class I integrons, which scientists have linked to multidrug resistance. The researchers processed sludge from a nearby treatment facility in lab-scale aerobic and anaerobic digesters at four different temperatures: 22°C, 37°C, 46 °C, and 55°C.

Quantitative polymerase chain reaction revealed that in the anaerobic reactor, the amounts of antibiotic resistance genes declined with increasing temperature. LaPara presumes that higher temperatures killed resistant bacteria or caused them to lose resistance genes. The effect was most dramatic for the integrase gene: At the highest temperature, the scientists could remove 99.99% of it, LaPara says. In contrast, during aerobic digestion, higher temperatures did not substantially change the prevalence of antibiotic-resistance genes. LaPara was surprised by the aerobic digestion results and plans further study.

Raising the temperature of anaerobic digestion at wastewater treatment plants should not be cost prohibitive, he says, because the digesting bacteria produce methane gas that can heat the reactor.

"This study provides a practical approach for reducing the spread of antibiotic resistance from wastewater treatment plants," comments Amy Pruden, an environmental engineer at Virginia Polytechnic Institute and State University. She adds that she is curious to see whether the approach works with resistance genes to other antibiotics.

Chemical & Engineering News
ISSN 0009-2347
Copyright © 2011 American Chemical Society
  • Print this article
  • Email the editor

Services & Tools

ACS Resources

ACS is the leading employment source for recruiting scientific professionals. ACS Careers and C&EN Classifieds provide employers direct access to scientific talent both in print and online. Jobseekers | Employers

» Join ACS

Join more than 161,000 professionals in the chemical sciences world-wide, as a member of the American Chemical Society.
» Join Now!