Shampoo Boosts Drug-resistant Bacteria

Scientists at Birmingham and Warwick universities have warned that fabric softeners, disinfectants, shampoos and other household products are spreading drug-resistant bacteria around Britain. Once these products are released into sewers and rivers they instigate the proliferation of drug-resistant microbes, increasing the likelihood that certain medicines will not be able to combat dangerous diseases.

The research suggests that the problem of drug resistance is not simply due to antibiotics being over-prescribed or poor hygiene standards in hospitals, although the emergence of deadly superbugs such as MRSA are not linked to the use of disinfectants.

“Our research shows drug resistance is not confined to hospitals, but is out in the community…It is spreading and all the time it is eroding our ability to control infections. It is extremely worrying,” Professor Liz Wellington of Warwick University told The Guardian.

The study evaluated soil and sewage sludge contaminated with quaternary ammonium compounds in the Midlands, the Cotswolds, Hertfordshire and other areas, for the presence of antibiotic-resistant genes, which they detected in high concentrations. 

Quaternary ammonium compounds are synthetic derivatives of ammonium chloride and are used as disinfectants and sanitisers for homes, farms, hospitals and offices; algaecides for swimming pools, industrial water reservoirs and farm ponds; antiseptics for cleaning wounds; surfactants, fabric softeners and antistatic agents in shampoos; surfactants and preservatives in a range of cosmetic products; softeners for textiles and paper products and preservatives and wetting agents in inhalers and nasal sprays. Examples include benzalkonium chloride, benzethonium chloride, cetalkonium chloride, cetrimide, stearalkonium chloride, quaternium-15 and quaternium-18. Every year huge amounts of these chemicals are flushed from homes and factories into sewers and rivers.

Although quaternary ammonium compounds are often used to kill undesirable microbes at high concentrations, the diluted concentrations detected within sewers, allow the bacteria to develop resistance, resulting in more virulent strains. 

“That is a natural evolutionary process,” Dr William Gaze of Warwick University said, “If other bacteria are killed, those that are resistant to QACs will survive and, without competition, will multiply in vast numbers. However, it turns out that the piece of DNA that confers that resistance 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…these are now poised to enter the food chain.”

Wellington added: “Once they are in the land, these bacteria will get into the bodies of agricultural workers or people who use the land recreationally and will form reservoirs of drug-resistant microbes that could pose all sorts of problems. This is going to need a great deal of monitoring.”

Source: The Guardian