Pollution makes bacteria more resistant – study

A STUDY which involves waterways in the Tyne catchment area has shown how pollution can increase antibiotic resistance in bacteria.

Research by Newcastle University and the Indian Institute of Technology in Delhi examined sediments from the Ganges and Yamuna Rivers in India and streams in the Tyne catchment.

The results show heavy metals, which are high in the River Tyne catchment due to historic mining and industrial activity, relate to antibiotic resistance levels in the river. The same was seen in the Indian rivers, especially in areas of industrial activity.

The study showed that metal pollution in the Tyne area from mining and industry of the past can cause bacteria to evolve to defend themselves.

The longer-term consequence is an increasing amount of bacteria which can develop resistance, including to antibiotics. “If we pollute the environment, we are putting stress on natural bacteria and they defend themselves by developing capacity which includes antibiotic resistance,” said Study co-author, Professor David Graham, of Newcastle University’s School of Engineering.

“Even in places where river quality is reactively good, like the Tyne, if we put in things like chemicals, nutrients and metals we are slowly providing an environment that allows bacteria to evolve to become stronger and more resistant to substances we might use to suppress them.”

Prof Graham said that any health threat from the Tyne network was small, given that people are unlikely to be exposed to sediment or river water.

But the longer-term bigger picture was an increase in the pool of bacteria which are resistant.

The study shows that specific metal combinations that promote the strongest bacterial responses are cobalt plus nickel, and the combination of cobalt, zinc and cadmium. Prof Graham said: “The work does not necessarily imply a health risk, but it shows that a river or stream without antibiotics pollution can still have elevated antibiotic resistance due to other pollutants, such as metals.

“However, in a river like the Yamuna, which has high metals in combination with many other pollutants, greater concerns about the spread of antibiotic resistance exist.”

Study lead author Dr Sonia Gupta said: “High metal exposure has the potential to co-select for antibiotic resistance in bacteria, making them potentially resistant to multiple antibiotics.

“The impacts of heavy metals-induced antibiotic resistance get exacerbated when high metal levels are combined with other pollutants such as antibiotics, detergents, and other chemicals.”

Antibiotic resistance is major global public health issue that has implications on the effective treatment of a growing number of infections caused by bacteria, parasites, viruses and fungi.