A first-ever global study led by a team of scientists from the University of York in the U.K. discovered that rivers around the world are widely contaminated with various antibiotics — some exceeding ‘safe’ levels by up to 300 times.
The study is the first to coordinate such a broad global survey, covering rivers in different parts of the world. It has examined levels of 14 common antibiotics from 711 sites in 72 countries across all continents, except Antarctica. John Wilkinson, one of the researchers involved in the project, said that this is the largest antibiotic survey ever conducted.
They found antibiotics in about 65% of the sites they have monitored — including rivers from the Thames, Danube, Chao Phraya, Mekong, Seine, Tiber, and Tigris. In a river in Bangladesh, Metronidazole, a drug used to treat bacterial infections including skin and mouth infections, has been found to exceed safe levels by 300 times. Although regarded as one of Europe’s cleanest rivers, five different antibiotics were found in London’s famous River Thames, while the Danube was Europe’s most contaminated river containing seven different types of antibiotics.
The most prevalent antibiotic among the samples was trimethoprim, which was detected at 307 of the 711 sites tested. Trimethoprim is a drug primarily used to treat urinary tract infections. Meanwhile, Ciprofloxacin, a drug used to treat various bacterial infections, was the drug that most frequently exceeded safe levels, surpassing the safety threshold in 51 places. Moreover, Clarithromycin, a drug used to treat respiratory tract infections, was found in concentrations four times higher than ‘safe’ levels.
Furthermore, Bangladesh, Kenya, Ghana, Pakistan, and Nigeria were sites where antibiotics exceeded ‘safe’ levels by the highest margin.
Antibiotics have saved countless lives from threats against bacterial infections since its inception in 1928. However, because of factors such as misuse and overuse of these drugs, bacteria have learned to evolve and adapt — making them antibiotic resistant. When bacteria become immune to the medicines we use to treat them, curing these infections will be challenging and costly since it requires a more potent kind of antibiotic to rehabilitate. Aside from resulting in more expensive medical costs, antibiotic resistance could also lead to extended hospital stays and an increasing number of deaths.
In the past years, cases of deaths due to antibiotic resistance has escalated at an alarming rate. A 2016 report by the United Nations’ Interagency Coordination Group on Antimicrobial Resistance discovered that drug-resistant diseases cause about 700,000 deaths worldwide a year, including 230,000 deaths from multidrug-resistant tuberculosis.
Last month, the United Nations already considered the resistance to antibiotics, antivirals, antifungals, and anti-protozoans as a “global crisis.” The U.K. Chief Medical Officer, Professor Dame Sally Davies, says the issue is getting worse every year, and it poses a “catastrophic threat” to our ability to treat bacterial infections in the future.
The findings of the study, stating that at least one antibiotic drug was discovered in 65% of all the samples, were not surprising says Emma Rosi, an aquatic ecologist at the Cary Institute of Ecosystem Studies, because “anywhere people use pharmaceuticals in their everyday lives, we see the evidence downstream.”
When people drink antibiotics, our bodies are not able to completely break down these drugs. Thus, the excess is eliminated from the body through urine or waste — which eventually gets flushed out into the bodies of water. The highest concentrations of many antibiotics were found in the bodies of water that are near wastewater treatment systems, sewage, and trash dumps.
Alarmingly, the results of the study indicating that there are unsafe levels of antibiotics present in natural systems could affect natural biological processes. Consequentially, bacteria could develop resistance.
Prof William Gaze, a microbial ecologist at the University of Exeter who studies antimicrobial resistance said that “a lot of the resistance genes we see in human pathogens originated from environmental bacteria.” He also said that even faint traces of antibiotics could have big effects on the development of resistance and that there is much more research to be done before scientists understand exactly how the evolution of antibiotic resistance works.
Dr. Gaze also stated that “by the time we have all the scientific evidence, it may be too late. We may have gotten ourselves to a post-antibiotic era when people are dying after being scratched by a rose in their garden and ending up with an untreatable infection.”