Environmentalists have found antibiotics and other drugs in river water around the world. The highest concentrations of medicinal substances were found in Pakistani rivers - in the Ravi River, scientists found a mixture of seven antibiotics with a total concentration of over three milligrams per liter. The authors presented the results of the study at the annual European conference of the Society for Environmental Toxicology and Environmental Chemistry SETAC, which takes place from May 26 to 30 in Helsinki, The Guardian briefly tells about the study.
Currently, more and more pathogenic microorganisms develop antibiotic resistance. And this is becoming a serious problem, since drugs no longer exist to treat some pathogens. Bacteria borrow genes for antibiotic resistance from various sources, including microorganisms from the environment, such as those that inhabit soil or water.
An international team of researchers led by Alistair Boxall from the University of York has carried out a global monitoring of medicines in rivers around the world. Scientists took 711 samples of river water in 71 countries of the world. In 65 percent of them, they found antibiotics, and other drugs were found in 50-80 percent of samples on different continents. In the rivers of Austria, Belgium, Iraq, Pakistan, Nigeria, Laos, the content of at least one antibiotic in river water was higher than PNEC (Predicted No Effect Concentration) - concentrations that, presumably, do not have a harmful effect on the environment.
The dirtiest rivers were African and Asian. In 55 percent of samples from African rivers, researchers found the antibiotic ciprofloxacin, which, among other things, is used to treat bronchitis, pneumonia and bacterial infections of the gastrointestinal tract. In the rivers of Asia, metformin was the most common drug (in 79 percent of samples), a drug used to treat type 2 diabetes. The Danube turned out to be the dirtiest of the European rivers. In water samples taken in Austria, the researchers found seven antibiotics, including clarithromycin, which is used to treat upper and lower respiratory tract infections. Five antibiotics were found in the Thames (which was considered one of the cleanest European rivers) and its tributaries. Among them was ciprofloxacin, the concentration of which was three times higher than PNEC.
The dirtiest rivers were found in Pakistan. In samples from the Ravi River, on the banks of which the capital of the country, Lahore, is located, there were seven antibiotics with a total concentration of 3.15 milligrams per liter. In other samples from Pakistani rivers, researchers counted 33 medicinal substances, including antibiotics.
“Many scientists and policymakers now recognize the role of the environment in the spread of antibiotic resistance,” said study leader Alastair Boxall. “Our results indicate that antibiotic contamination of river water may be an important factor in this. Solving the problem will take a titanic effort and will require investment in infrastructure to treat waste and wastewater, tighter regulation and clean up already contaminated sites.”
Microbiologists have recently monitored the transfer of antibiotic resistance genes between bacterial cells in real time. With the help of intravital microscopy, they followed the process of transfer of the tetracycline resistance gene between E. coli cells. And just before that, researchers showed that antibiotic-resistant bacteria can spread very quickly around the world. For example, the blaNDM-1 gene, which provides bacteria with resistance to beta-lactam antibiotics (these include penicillin), made it from India to Spitsbergen in five years.
Ekaterina Rusakova
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