May 29, 2009

Antibiotic resistant bacteria in sludge

An antibiotic resistant bacteria was found in 79 percent of Swedish sewage sludge samples tested, researchers in Scandinavia say.

Study leader Leena Sahlstrom of the Finnish Food Safety Authority, working with the Swedish National Veterinary Institute, says the danger the bacteria -- vancomycin resistant enterococci -- present in the wastewater treatment by-product and used as a fertilizer or soil conditioner could pass its superbug resistance genes to other bacteria in the human food chain.

Antimicrobial resistance is a serious threat in veterinary medicine and human healthcare, Sahlstrom says in a statement. Resistance genes can spread from animals, through the food chain, and back to humans. Sewage sludge may act as one link in this chain.

Sahlstrom and colleagues examined sewage sludge collected from a wastewater treatment plant in Uppsala, Sweden, every week for four months -- for a total of 77 samples.

Our results demonstrate a need for more efficient hygienic treatment of sewage sludge, in order to avoid possible spread of antimicrobial resistance through use of sewage sludge on arable land, Sahlstrom says.

The study is published in the journal Acta Veterinaria Scandinavica.