Antibiotic resistance is one of the most significant threats to the future of human health. But the steps we take to reduce our exposure to bacteria and infections could actually be making the situation worse. Chlorine used in many wastewater treatment plants is reacting with drugs dumped in the water to boost their antibiotic properties. This could, in turn, lead to the development of antibiotic-resistant 'super' microbes and weaken our ability to fight infections, scientists have warned.
Chemists have found that chlorine used in many wastewater treatment plants is reacting with drugs dumped in the water to boost their aantibioticproperties. This in turn can lead to the development of antibiotic-resistant microbes and weakens how we fight infections
The findings were presented at the National Meeting and Exposition of the American Chemical Society (ACS) by Dr Olya Keen from the University of North Carolina at Charlotte. Dr Keen and a team of her students and colleagues ran several lab experiments on wastewater.
They found that exposing doxycycline - a common antibiotic used to treat infections including chlamydia and acne - to the chlorine in wastewater increased the antibiotic properties of their samples.
This means chlorine is not only failing to strip pharmaceuticals from the water, but that trace levels of these substances are entering waterways. 'Surprisingly, we found that the products formed in the lab sample were even stronger antibiotics than doxycycline, the parent and starting compound,' Dr Keen said. 'Pharmaceuticals that get out into the environment can harm aquatic life, making them react slowly in the wild and disrupting their hormone systems.'
She added that increased antibiotic exposure, even at low levels in the environment, can lead to development of antibiotic-resistant bacteria and a general weakening of antibiotics' abilities to fight bacterial infections in humans. And the compounds found in the samples, known as 'transformation products' appear to be previously unidentified antibiotics. 'Treated wastewater is one of the major sources of pharmaceuticals and antibiotics in the environment,' continued Dr Keen. 'Wastewater treatment facilities were not designed to remove these drugs. 'The molecules are typically very stable and do not easily get biodegraded. Instead, most just pass through the treatment facility and into the aquatic environment.'
Chlorine is added to swimming pool water to keep it clear of certain bacteria.
But previous research has shown that elements of urine including urea, uric acid, and amino acids, interact with chlorine to produce potentially hazardous disinfection by-products in swimming pools.
The disinfection by-products included cyanogen chloride (CNCl) and trichloramine (NCl3).
Cyanogen chloride is a toxic compound that affects many organs, including the lungs, heart and central nervous system by inhalation.
Trichloramine has been associated with acute lung injury in accidental, occupational, or recreational exposures to chlorine-based disinfectants.
This research suggested that about 93 per cent of uric acid introduced to pools comes from human urine.
In lab experiments the researchers found that exposing doxycycline - a common antibiotic used to treat infections including chlamydia and acne - to the chlorine in wastewater increased the antibiotic properties of their samples. Trace levels of these substances are now entering waterways
The researchers are now calling for disinfection practices at wastewater treatment plants to be changed. Dr Keen explained that the best solution may be to decrease the amount of these drugs that reach a treatment plant in the first place. The disposal of pharmaceuticals is not currently regulated, for example.