Bacteria resistant to some antibiotics have been found in Toronto tap water, a University of Michigan scientist says.
The water remains safe to drink, he said, but the finding raises the possibility that disease-causing bacteria will pick up the resistance genes.
In the United States, researchers have found bacteria that have evolved to become resistant to some antibiotics in some municipal water supplies.
At his lab in Ann Arbor, Mich., microbiologist Prof. Chuanwu Xi showed a stack of petri dishes, some filled with yellow dots of bacteria that should have been killed off by antibiotics. The source of the bacteria was drinking water from several communities in Ohio and Michigan.
“In tap water in Toronto, there’s antibiotic-resistant bacteria,” Xi said, after testing water samples provided by CBC News.
The researchers don’t know what kinds of bacteria they’ve found, just that they can’t be killed by antibiotics.
But most bacteria in the environment are not the kinds that cause human disease, so the water is safe to drink, the researchers said.
The real concern is the genetic pollution created by antibiotic-resistant genes circulating in the environment, and the risk that human pathogens will pick up those resistant genes, said Gerry Wright, a researcher at McMaster University in Hamilton.
Bacteria “have this remarkable ability to take up drug-resistance genes from their neighbours,” Wright said. “In some cases, they can collect dozens of drug-resistance genes and incorporate them into their genomes. It’s really quite astounding.”
Since overuse of antibiotics helps fuel drug-resistant bugs, public health officials continue to fear they may run out of options to treat human infections, he said.
Julianna Cummins, National Post
Published: Tuesday, October 27, 2009