Unwanted side effects. Water treatment plants that apply biological technologies are becoming factories of super resistant bacteria. “Superpathogen incubators”, he calls them an international study in which the Center for Ecological Research (CREAF) of the CSIC has participated, after analyzing how wastewater treatment plants that apply environmental biotechnology constitute a source of proliferation and spread of these harmful microorganisms. “A real and emerging threat to health”, they define it.
INTERVIEW | “We are running out of antibiotics”
Human activities generate a large amount of wastewater: about 330,000 cubic hectometres per year containing heavy metals, carbohydrates, antimicrobials and pathogens that pollute the environment and spread disease. Biotechnologies that use microbes to degrade pollution are applied mostly in treatment plants because they are an inexpensive formula, the researchers explain. For example, in China, the application of these techniques costs $ 0.1 per cubic meter of treated water. “They are valuable, but at the same time they induce the risks of hatching and expanding superpathogens.”
The point is that, over time, the millions of species of microbes that inhabit sewage plants to treat pollutants find a way to evolve and shield themselves. “Microbes use strategies to survive contaminants that are very similar to those they use to resist antimicrobials,” explains CREAF researcher Josep Peñuelas. This ecologist adds that “during the long-term operation of these treatment plants, pathogens multiply, exchange genes and evolve to resist and survive the multiple pollutants in these waters, which, unfortunately, also leads them to increase their resistance. to antimicrobial drugs “.
Antibiotic resistant bacteria are a problem of the first magnitude. Warnings about its growth and health consequences have been repeated for years at the international and national level. In fact, the UN has calculated that each year some 700,000 people die from diseases caused by pathogens immune to medicines. “If urgent measures are not taken, they could cause ten million deaths annually in 2050,” it was warned in the session of the General Assembly last April.
“As the present and growing pandemic that it is, antimicrobial resistance must be a central part of preparing for a future health emergency,” said then the president of the UN Assembly, the Turkish Volkan Bozkir. The director of the World Health Organization, Tedros Adhanom, has stressed that it is “vital that we give it the same sense of urgency that we have seen with COVID-19.”
Spain is not at all alien to this problem of superbugs. Cases of infections with resistant microbes have been growing, putting many drugs in the orange and red zones. The Ministry of Health calculated that 2,956 people died in Spain from this cause in 2016 and treating resistant infections involved an effort of at least 150 million euros.
Spain is one of the countries that consume the most antibiotics in the European Union, despite experiencing a 7% decrease between 2015 and 2018. The decrease in the sale of veterinary antibiotics was 30%, a significant figure, since Spain led by This classification stands out, an essential point in the creation of superbugs, according to the National Plan against resistance approved in 2019 and which should last until 2021.
The real danger is that doctors end up running out of medicine for many infections. Diseases that jump from animals to humans through food and sexually transmitted diseases are the most worrisome, as the European Center for Disease Control has explained on numerous occasions.
Resistance is created by the mutations that pathogens generate when they are in a hostile environment. Abuse of antibiotics in livestock or people creates these conditions. But it has also been found that environmental pollution is a perfect breeding ground: the chemical residues that end up in the water and the soil cause the bacteria to develop these resistances. Now the treatment plants are added, where the bacteria mutate and are selected to be stronger and stronger. And once mutated, they can travel to infect people with their newly developed genetic armor.
More worm monitoring and filters
The work of the Chinese scientists and CREAF shows that these harmful and evolved microbes have the possibility of being transmitted to humans “by accidental contact with regenerated water – which leaves the plant – and with microparticles that pass into the air”. They also find a route of transmission in “contaminated food” by the very water that flows from the treatment plant “that irrigates the cultivated fields.”
“The COVID-19 pandemic has already shown that viruses are spread and detected in wastewater treatment systems, but little has been done to eliminate the health threat of superpathogens,” Josep Peñuelas explains.
This international team asks the health authorities not to look the other way and recognize the threat they pose to public health. In this way, they argue, governments can “guide the public and supervise the industry.” In this sense, they consider it necessary “to establish stricter standards that limit the microbial pathogens that a water treatment plant can emit.” In addition, they ask to implement new technologies that not only eliminate pollutants from water, but also eliminate superpathogens that are generated in water treatment plants. An example: using worms as a filter, since “they can consume and eliminate pathogens.”