Wastewater Tells Story of Regional Antibiotic Use

Pseudomonas aeruginosa bacteria is a germ that can evolve to resist antibiotics. “Nightmare bacteria” with unusual resistance to antibiotics of last resort were found more than 200 times in the United States last year. (Illustration via CDC)

(CN) – Bacteria are resourceful, a point made clear by findings of antibiotic-resistant germs surviving the trip from toilet to water treatment plant. They also tell the tale of their host humans’ sometimes overreliance on antibiotics.

The World Health Organization reports that without a proper defense against antimicrobial-resistant superbugs, infections will become a higher risk for medical procedures and hospital patients, but also for people prone to catching pneumonia. Currently, antibiotic-resistant germs can be found across all continents.

Bacteria live in the human gut and do not cause disease in that stage. It’s after a person flushes their toilet and sends the germs into the wide world that has researchers’ attention.

Antibiotic-resistant bacteria were capable of multiplying in at least one Portugal waste water treatment plant with the facility meant to clean sewage water in fact becoming an incubator for germs, according to the study published Wednesday in the journal Science Advances.

Researchers from the University of Helsinki in Finland studied the levels of antibiotic resistance found in water at several urban wastewater treatment plants across Europe, including facilities in Portugal, Spain, Ireland, Cyprus, Germany, Finland and Norway. They found people living in Spain, Portugal, Cyprus and Ireland tended to send higher levels of antibiotic-resistant bacteria down the toilet than those who lived in Norway, Finland and Germany.

That’s on par for antibiotic-resistant germs studied in clinics. People living in Southern Europe tend to consume more antibiotics than their northern neighbors, raising the risk of antibiotic-resistant bacteria.

Treatment plants effectively removed the resistant bacteria through the purification process, though a plant in Portugal became the ideal incubator for germs to thrive. The study authors said several variables could explain why the bacteria was able to reproduce, including temperature, the age of the treatment plant and other reactions of lactic bacteria acid and feces in the water.

The findings underscore the need for further study to assess the risk associated with antibiotic-resistant bacteria in wastewater. One scenario presented by researchers involves the resistant bacteria surviving the purification process, with the treated water then being used to irrigate farmland and the bacteria making its way into the food chain.

“We need more research findings from countries with high antibiotic consumption and less developed wastewater treatment practices,” microbiologist Marko Virta from the University of Helsinki said.

The researchers will next explore treatment techniques in Asia and West Africa.

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