MicrobeWorld

New study suggests waste treatment process can have an unintended consequence of spreading of extra-hardy bacteria. "To determine if sewage-treatment plants might be a source of resistant bugs, Chuanwu and fellow researchers collected several species of the common bacteria Acinetobacter from a plant in Ann Arbor, Mich. that dumps its effluent into the Huron River.

They exposed the bacteria to various antibiotics and cocktails of drugs, and found a significant increase in the percentage of Acinetobacter that were resistant after each stage of treatment. And while the final treatment process killed all but a tiny fraction of the bugs before releasing the water to the environment, the proportion of resistant bacteria was much higher among those that made it back to the river than those collected upstream from the plant."