Water: The Invisible Link in the Spread of Antibiotic Resistance

In the global spread of antibiotic resistance, water acts as an invisible bridge between humans, animals, and the environment.

For many years, the misuse and overuse of antimicrobials have driven the emergence and spread of resistant microorganisms, to the point of being described as a “silent pandemic.”
But this problem does not only affect people: it also impacts animals and the environment.

One Health.

The role of water in antibiotic resistance

Within the environment, water is considered one of the most important vehicles for bacteria and resistance genes to antibiotics.

Wastewater —coming from households, hospitals, or farms— is treated in treatment plants to remove organic matter, pollutants, and microorganisms. Part of this treated water returns to rivers, and another part is reused to irrigate crops, streets, or parks. With drought episodes becoming more frequent, the use of this reclaimed water will continue to grow.

Although treatment eliminates most fecal bacteria, environmental bacteria persist in reclaimed water (considered “normal” in the environment), and these are capable of acquiring and transferring resistance genes.

Why is it a risk?

These environmental bacteria rarely cause serious infections, except in immunocompromised people, so they are considered opportunistic pathogens. However, they can act as “bridges” of resistance: when in contact with pathogenic bacteria, they can transfer the acquired resistance genes, making them more difficult to treat if they cause an infection.

From water to plate: a foodborne risk

Irrigation with contaminated water can transmit resistant bacteria to food. An example of vegetable contamination was the outbreak attributed to the “Spanish cucumbers” (eventually caused by soybean sprouts irrigated with fecal water in Germany), which affected more than 2,000 people and caused 22 deaths.

Water connects humans, animals, and the environment: it is a key vehicle in the spread of antibiotic resistance. Protecting water resources and improving wastewater treatment are essential steps to curb this global threat.

The role of livestock and chemical pollution

The historical misuse of antibiotics in food-producing animals —including fish— has contributed to this crisis. Although it is now regulated, we are paying the price for previous decades. Antibiotic-resistant bacteria of animal origin can reach water through feces.
In addition, discharges of chemical substances, antibiotics, and other waste into rivers and seas can promote bacterial mutations that increase their antibiotic resistance, as bacteria try to protect themselves from these substances, sometimes by expressing specific genes that confer resistance to antibiotics.

Protecting water, protecting health

Water connects humans, animals, and the environment: it is a key vehicle in the spread of antibiotic resistance. Therefore, protecting water resources and improving wastewater treatment are essential steps to curb this global threat.