DECADES of man-made pollution of the environment is leaving a legacy which could see disease-fighting drugs rendered increasingly ineffective, North East scientists fear.
Soil studies by a Newcastle University team indicate a rising level of bacteria in nature with a gene which is resistant to the antibiotic drugs that have improved health dramatically over the last 50 years or so.
A rising “background” level of resistance makes it more likely that pathogenic, or disease-causing bacteria, acquire the resistant gene.
“Because of background resistance increasing we could be facing a future where more and more drugs don’t work or work as effectively,” said David Graham, Newcastle University Professor of Ecosystems Engineering.
“What we have found is that background levels have increased and are increasing, and this should set alarm bells ringing.”
He warned that this raised the prospect of a future return to the days of big epidemics. “There has been growing concern about increasing antibiotic resistance and the threat it poses to our health, which is best evidenced by MRSA,” said Prof Graham, who is based in the School of Civil Engineering and Geosciences and who led the research.
“Despite increasingly stringent controls on our use of antibiotics, the background level of antibiotic resistant genes, which are markers for potential resistance, continues to rise in soils.
“This increases the chances of a resistant gene in a harmless bacteria being passed onto a disease-causing pathogen, such as MRSA, with obvious consequences.” Prof Graham said that years of pollution had placed pressure on organisms, many of which live naturally in the soil. Antibiotics pass into the environment from waste from humans and farm animals, which has seen organisms evolve to defend themselves.
Heavy metal pollution also has the same effect, with the resistant gene created in bacteria also working against antibiotics.
Prof Graham said: “We are contending that in 200 years of industrial activity we have slowly increased the level of background resistance.
“We now have more resistance in general in nature.
“We have caused evolution to occur with bacteria becoming more resistant to antibiotics. This can lead to a loss of effectiveness of antibiotics and a greater chance that the drugs we need to treat disease will not work.”
Prof Graham said that 150 years ago life expectancy was moderately low. “People got sick and died. But with the use of antibiotics, life expectancy has increased drastically,” he said.
“Now we have a different type of problem. We have some pathogens which are resistant to the drugs which have made us more healthy.
“We have already done the ‘easy’ drugs and its is getting harder and more expensive to make drugs which do work.”
Of the Newcastle findings, Prof Graham said: “I think it tells us we have changed the environment and it is very probable that is the reason why drugs are less effective.”
He said that more studies are desperately needed between environmental and public health researchers to determine whether this increasing pool of resistance is contributing to harmful bacteria, such as MRSA.