The U.N. warned Tuesday of a ticking time bomb of drug-resistant germs brewing in the natural environment, aided by humans dumping antibiotics and chemicals into the water and soil.
If this continues, people will be at an even higher risk of contracting diseases, incurable by existing antibiotics, from swimming in the sea or other seemingly innocuous activities, a report warned.
"Around the world, discharge from municipal, agricultural and industrial waste in the environment means it is common to find antibiotic concentrations in many rivers, sediments and soils," the investigation said.
"It is steadily driving the evolution of resistant bacteria," it warned bluntly. "A drug that once protected our health is now in danger of very quietly destroying it."
The report, entitled Frontiers 2017, was published at the U.N. Environment Assembly, the world's paramount gathering on environmental matters.
"We may enter what people are calling a post-antibiotic era, so we go back to the pre-1940s when simple infection [...] will become very difficult, if not impossible" to treat, Will Gaze of the University of Exeter, who co-authored the new report, told AFP.
Bacteria that survive antibiotics can transfer genes which confer drug resistance directly between one another.
The genes can be passed on to future generations or mutate further in the germ's DNA.
Today, about 70 to 80 percent of all antibiotics that humans take, or give to farm animals to prevent them from falling sick, are excreted back into the environment, partly through wastewater and agriculture.
"So the majority of those hundreds of thousands of tons of antibiotics produced every year end up in the environment," Gaze explained.
Humans and animals also excrete germs, both resistant and nonresistant, into the environment, where they mix with the antibiotics and other, naturally-occurring bacteria.
Add to the mix antibacterial products such as disinfectants and heavy metals that are toxic to germs, and ideal conditions may be created for bacteria to develop drug-resistance in places where humans will come in contact with them.
"If we go into river systems, we see really big increases in resistance downstream [from] wastewater treatment plants [...] and associated with certain types of land use, so grazing land for example," said Gaze.
"If you go into coastal waters where [...] you might be heavily exposed to the environment, we know that we can measure quite high numbers of resistant bacteria in there."