Antibiotic resistance is also referred to as the ‘silent pandemic’. Tens of thousands of people die each year from resistant bacteria. The sewer appears to be a much larger breeding ground for these bacteria than previously thought.
According to Swedish researchers, sewage water has a number of unique properties that make it perfect for harmless microbes to develop into pathogenic bacteria. Not pleasant news, but it is positive that with the knowledge we have gained we can devise a plan to limit the consequences.
Hundreds of millions of years old
Science didn’t invent antibiotics in the lab. In fact, micro-organisms produced the first antibiotic molecules long before the first human beings walked the earth. This is how bacteria developed the special ability to defend themselves against other microbes. We copied the trick from them, automated the production of the active substances and then used it worldwide against all kinds of bacterial and fungal infections.
Unfortunately, antibiotics have become so overused in the medical and agricultural world over the past few decades that we’ve given the pathogens a chance to fight back by developing an evolutionary antidote. The bacteria collect more and more resistant genes in their DNA. This is a multi-step process in which the pieces of DNA containing antibiotic information are first released from the chromosomes of the benign bacteria in which they are attached, after which they float freely outside the cells. These gene packages can then jump to another microbe species and eventually end up with a pathogen.
Drietrapsraket
The research from the Swedish biologists provides evidence of how genes detach, slip out of the cell and make their way to another organism in sewage water in one piece. Previous studies have already shown that antibiotic residues in wastewater can accelerate the development of antibiotic-resistant bacteria. It now appears that resistant genes in the dirty water can also jump relatively easily from benign bacteria to pathogenic species. For this, both the good and the bad microbes must be present in the water, together with the antibiotic residues and the specific piece of resistant chromosome, otherwise the microscopic cross-pollination will not work.
The microbiologists studied DNA from thousands of samples from different environments and were stunned when it turned out that this complicated process hardly ever took place in the intestines of humans or animals, but did take place in all kinds of wastewater samples collected all over the world. “In our fight against antibiotic resistance, we should not only focus on preventing the spread of resistant bacteria that are already in circulation, but we should also limit the birth of new species as much as possible,” says lead researcher Fanny Berglund of the University of Gothenburg.
Stop overusing antibiotics
The team has already published many studies showing that there is a wide variation in resistance genes, far more than is seen in disease-causing bacteria. Gene packets can jump from species to species in an external environment and eventually arrive at dangerous microbes that can become resistant to certain antibiotics. The researchers explain that it is therefore not a good idea to pollute the environment with large amounts of antibiotics: it is a trigger for the evolution of resistant microorganisms.
“A lot of attention is paid to reducing the use of antibiotics in humans and animals. This is certainly important, but our research shows that it is also very useful to pay attention to what happens in the sewage. In our wastewater, bacteria get the chance to exchange genes. It is an ideal breeding ground for antibiotic-resistant pathogens,” concludes Berglund.
Antibiotic resistance
At the end of last year, the European Center for Disease Prevention and Control, ECDC, sounded the alarm: every year about 35,000 Europeans die from antibiotic-resistant bacteria. That number is increasing. According to some scientists, more people will die from the resistant bacteria than from cancer by 2050. It is therefore important to do everything possible to reduce this resistance by, for example, also looking at sewage water.