Airplane toilet water may help combat the next pandemic

Airplane bathrooms aren’t exactly the most pleasant, comfortable, or even hygienic experiences. But their sheer number of daily occupants while cruising at 30,000 feet may present a major public health opportunity. As everyday pathogens continue developing into deadly superbug variants, researchers believe the collective wastewater inside commercial aircraft can provide an easy-to-access, cheap, and noninvasive source of real-time pandemic monitoring.

While disinfectants provide an immediate safeguard against harmful diseases and bacteria, their continued overuse has created a problem. Over the past 50 years, epidemiologists have repeatedly highlighted the dangers of rapidly spreading, antimicrobial resistant (AMR) diseases. The reason behind the health hazard is simple: germs and bacteria that survive an encounter with hand sanitizer continue to live and breed another day. These organisms can then develop over countless generations into AMR superbugs that aren’t susceptible to current medical treatments. Studies indicate this plague of superbugs may kill 40 to 50 million people by 2050—surpassing even cancer’s fatality rate.

To help potentially curb those numbers, an international team of pathogen experts recently analyzed the bathroom wastewater from 44 international flights arriving into Australia from nine different countries. Researchers used advanced molecular screening methods to examine the genetic structures of any potential superbugs with antibiotic resistance genes. As detailed in a study recently published in the journal Microbiology Spectrum, the handful of trips collectively fostered nine “high-priority,” drug-resistant superbugs, including Salmonella and Staphylococcus aureus.

It didn’t end there. The team detected five of the study’s nine high-priority superbugs in all 44 flight wastewater samples, and flagged 17 of those samples for containing a gene that boosted resistance to existing last-resort antibiotics. An important additional finding was that Australia’s urban wastewater sample lacked this same gene, indicating it most likely arrived from international travel. The presence of antibiotic resistant genes also varied across each aircraft’s country of origin, possibly due to regional antibiotic use, population density, public health policies, and water sanitation among other factors.

The study’s authors also tested the efficacy of disinfectants used in the sampled airplane toilets.They learned that the germs’ nucleic acids remained stable for as long as 24 hours after treatment—even in cases involving high-grade cleaning supplies. Although not the rosiest of news, the upshot is that it revealed aircraft wastewater can remain a reliable source of public health information for an extended period of time.

“This is a proof-of-concept with real-world potential,” microbial researcher and study co-author Warish Ahmed said in a statement. “We now have the tools to turn aircraft toilets into an early-warning disease system to better manage public health.”

“International travel is one of the major drivers of AMR spread,” added study co-author and ecoscientist Yawen Liu. “By monitoring aircraft wastewater, we can potentially detect and track antibiotic resistance genes before they become established in local environments.”