Polluted city air may contain ''superbugs''

Beijing, November 20

Polluted city air may be means of transmission for 'superbugs', warn scientists who have found that air samples from Beijing contain DNA from genes that make bacteria resistant to the most powerful antibiotics.

"This may be a more important means of transmission than previously thought," said Joakim Larsson, professor at Sahlgrenska Academy in Sweden.

The researchers looked for genes that make bacteria resistant to antibiotics in a total of 864 samples of DNA collected from humans, animals and different environments worldwide.

"We studied only a small number of air samples, so to generalise, we need to examine the air from more places. But the air samples we did analyse showed a wide mix of different resistance genes," said Larsson, director of the Centre for Antibiotic Resistance Research at the University of Gothenburg in Sweden.

"Of particular concern is that we found a series of genes that provide resistance to carbapenems, a group of last resort antibiotics taken for infections caused by bacteria that are often very difficult to treat," he said.

The results do not show whether the sampled bacteria were actually alive in the air, which would make them a real threat.

"It is reasonable to believe that there is a mixture of live and dead bacteria, based on experience from other studies of air," said Larsson.

The next step for the research is to find if resistance spreads through air from European sewage treatment plants.

"We're going to let treatment plant employees carry air samplers. We will also study their bacterial flora and flora of people who live very close and farther away, and see if there seems to be a connection to the treatment plants," said Larsson. — PTI