Antibiotic-Resistant Bacteria in Pig Waste

Researchers at Birmingham and Warwick University have discovered a link between the antibiotics used to treat farm animals - in particular pigs - and the spread drug resistance bacteria in the soil.

In the recently published study 'Is pollution driving antibiotic resistance?' published in the Planet Earth quarterly magazine of the Natural Environment Research Council, Dr William Gaze of Warwick University found that bacteria in samples of pig slurry possessed high levels of antibiotic-resistant genes. The high levels of antibiotic-resistant bacteria in the soil increased fears that strains of resistant bacteria could enter the food chain.

However, study also suggests that the problem of antibiotic-resistant bacteria may be being exasperated by the chemicals in common household cleaning products. Dr William Gaze worries that the 11 billion liters of water discarded from the houses and factories and homes in England, which are contaminated with fabric softeners, disinfectants, shampoos and other common cleaning products are triggering the growth of drug-resistant bacteria.

'Is pollution driving antibiotic resistance?' concludes that it is not the over-prescription of antibiotics that is increasing the amount of antibiotic-resistant bacteria, but rather the much more ubiquitous problem of pollution. The Birmingham and Warwick University study have found a dangerous connection between resistance to certain household cleaning products and resistance to antibiotics.

"That is a natural evolutionary process," said Gaze in a recent interview. "If other bacteria are killed [by household cleaning products,] those that are resistant...will survive and, without competition, will multiply in vast numbers. However, it turns out that the piece of DNA that confers that resistance [to household cleaning products] also contains genes that confer resistance to antibiotics. In this way, we have created an ideal environment for the emergence of antibiotic-resistant bacteria in our drains and sewers. These microbes are now being spread round the country in river water and in sewage sludge used on farms."

The fear expressed by some is that once the antibiotic-resistant bacteria are in the soil they will eventually enter the bodies of farm animals and agricultural workers. Once the antibiotic-resistant bacteria move into the food chain or the general population, the problem becomes much more difficult to manage.

In order to prevent the evolution of antibiotic-resistant bacteria into the food chain and the general population, there seems to be but one solution. Change the way we dispose of our household cleaning products.

Dr William Gaze, Is pollution driving antibiotic resistance?, planetearth.nerc.ac.uk

Robin McKie, Shampoo in the water supply triggers growth of deadly drug-resistant bugs, www.guardian.co.uk