Cowles called the study's findings "very surprising" and said if they are accurate, "that's pretty significant," he said. "That particular facility puts out one of the cleanest effluents in the country. If they're really showing that, then that's a wakeup call."
"Wastewater operators are concerned" about antibiotic resistance, Cowles said, "but it's a matter of needing research."
It's also a matter of cost.
Treatment plants use chlorine or ultraviolet light, or both, to kill microorganisms before discharging effluent to the environment, and although "in general, it's relatively safe," neither method kills all bacteria, Cowles said. For the right price, though, plant operators could wipe them out through reverse osmosis or the use of activated carbon.
"Is it possible to sterilize it? Of course," he said. A project in Orange County, Calif., for example, uses reverse osmosis and other advanced technologies to render sewage discharge pure enough to recycle as drinking water.
"It's a matter of money," said Cowles. "But it's very unlikely that the American public would tolerate the cost of doing that."
It's also unclear whether the risk of letting a few bugs survive in effluent warrants the high cost of completely eradicating them, he added.
"The environment provides the opportunity for infection no matter where you are, upstream or downstream," he said.
Meanwhile, according to Steitz, there's an ongoing arms race between superbugs and the medical world.
"Evolution trumps intelligent design," he said. "Even though you get really smart drugs, they'll eventually get around it."
This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.