Airplane Toilets as well as the Next Pandemic, with Dr. Warish Ahmed

I spoke with Dr. Warish Ahmed, Principal Research Scientist at CSIRO, Australia’s national science agency, whose team is pioneering the use of airplane wastewater to track superbugs before they cross borders. Our conversation centers on hisrecent studyin Microbiology Spectrum, where he and colleagues analyzed wastewater from international flights to detect antibiotic resistance genes and high-risk pathogen. This was originally posted in myNewsletter Here. First, will you tell us about yourself and how you became interested in this topic? I’m a Principal Research Scientist at CSIRO’s Environment Research Unit, where I focus on environmental microbiology, particularly tracking pathogens and antibiotic resistance in wastewater and chemical-free water systems. My journey into this field began with a fascination for how microscopic organisms can have such a profound impact on public physical wellness and ecosystems. It’s like detective work; piecing together clues from the environment to protect communities. In 2020, our team published the detection of SARS-CoV-2 in wastewater in AustraliaFirst confirmed detection of SARS-CoV-2. It was a proof-of-concept study showing how wastewater surveillance could monitor COVID-19 in communities. That work opened my eyes to the power of wastewater as a public vitality tool. Later, an idea came from our collaborator, Prof. Jochen Mueller at the University of Queensland: Why not test wastewater from aircraft? This led toanother studywhere we detected SARS-CoV-2 RNA in wastewater from commercial planes and cruise ships. It showed us that aircraft wastewater could potentially act as an early warning system for assessing the presence of COVID-19 infected travellers. From there, my interest broadened to using wastewater to monitor global well-being threats, especially antimicrobial resistance. By 2050, superbugs could cause more deaths than cancer. Testing plane wastewater provides valuable insight into resistant bacteria crossing borders before they become a local problem. It’s like tapping into a hidden goldmine of data: every flight carries invisible clues about emerging well-being risks. That’s what drives me – using science to stay one step ahead of these threats. How big of an issue is antimicrobial resistance (AMR) globally, and why could try to the public care about it? Antimicrobial resistance is a global concern. When bacteria evolve to resist antibiotics, infections become much harder to treat. People stay sicker for longer, treatments become more expensive and complicated. It’s like a silent pandemic creeping up on us. Right now, AMR is already linked to millions of deaths each year, and experts warn that by 2050, it could surpass cancer as a leading cause of death. That’s why this matters to all of us, if antibiotics lose their effectiveness, everyday physical wellness issues could become life-or-death battles. You analyzed wastewater from 44 repatriation flights coming from nine countries. Why were these flights chosen, and how well do they reflect global travel patterns? We selected those 44 repatriation flights because they were part of Australia’sCOVID-19 repatriation programwhich brought Australians home from nine different countries during the pandemic. These samples were initially tested for the presence of SARS-CoV-2 and then archived for retrospective analysis. These flights offered a unique opportunity to sample wastewater from passengers arriving from diverse regions, each with distinct antibiotic usage patterns and healthcare systems. The samples used in this study were collected during the COVID-19 pandemic so they do not perfectly mirror regular global travel patterns. Still, they gave us a valuable snapshot of microbial pathogens and antibiotic resistance genes (ARGs) moving across borders. You found ESKAPE pathogens and several resistance genes, some present in every sample. What do those findings tell us about the spread of antimicrobial resistance through travel? ESKAPE refers to a group of hospital pathogens that often carry resistance genes, making them especially hard to treat. We detected five types of antibiotic-resistant ESKAPE pathogens typically associated with hospital environments. We also identified several resistance genes, one that was present in wastewater from 17 international flights but had not yet been detected in Australia’s urban wastewater. These findings highlight that international travel is a pathway for superbugs which could potentially spread into local environments, hospitals, or communities, making infections more difficult to treat. You describe aircraft wastewater as a “non-invasive, cost-effective early warning” system. How could airports or public well-being programs realistically use this approach? Aircraft wastewater analysis is a complementary tool for public physical wellness surveillance because it’s non-invasive and cost-effective. Major international airports like Singapore, Dubai, or London, could establish daily ritual wastewater surveillance networks for arriving flights or from airport waste streams. Public mind-body health experts could then regularly test these samples for high-priority pathogens, especially those not yet seen in local systems. The data generated by analysing wastewater samples could nurture into global databases helping scientists map the spread of AMR. Major hubs, where flights from all over the world converge, would beideal spotsfor this surveillance, acting as sentinels for global mind-body health threats. Why isn’t current surveillance (like airport screening or municipal wastewater testing) enough? What unique gap does aircraft wastewater fill? Airport screenings typically focus on visible symptoms or specific diseases like fever checks for known threats, but they can’t detect silent threats like resistant bacteria that passengers may carry unknowingly. Municipal wastewater testing is a complementary tool for monitoring which pathogens are circulating within a community. But aircraft wastewater fills a critical gap by providing us a snapshot of what’s coming into a country before it blends into the local environment. It’s a proactive way to track the global movement of AMR. How confident are you that resistance genes remain detectable even after hours of flight time, disinfectants, and storage conditions? I’m confident that resistance genes remain detectable in aircraft wastewater even after long flights and exposure to harsh conditions. We specifically tested this in our study, and the results were clear: even after 24 hours and exposure to strong disinfectants used in aircraft toilets, the genetic material from resistant bacteria remained detectable. This stability is what makes aircraft wastewater a reliable tool for surveillance. It means we can trust the data we collect whether it’s from a short regional flight or a long-haul international flight. This was a proof-of-concept study. What are the next steps for this research? There’s still a significant work ahead to make aircraft wastewater surveillance a practical tool for tracking AMR and other pathogens of interest. We’re building on what we’ve already learned to support its usefulness in informing public holistic health. The first step is to adopt advanced genomic sequencing. Unlike the targeted qPCR assays used in the study, sequencing allows us to detect a much broader range of microbes. This will give us a clearer, more detailed picture of the potential threats coming off those planes. Looking ahead, we also want to make the tool itself more practical – faster, cheaper, and automated. The goal is to weave aircraft wastewater surveillance into global mind-body health systems and use as a complementary tool to fight against AMR or other microbial threats. Was there a result in your study that truly surprised you? Absolutely, we identified a resistance gene for last-resort antibiotics in the wastewater from 17 of those repatriation flights, one that had not been detected in Australia’s urban wastewater at the time of sampling. It suggests that international travel was potentially bringing this gene into the country, highlighting how quickly AMR can cross borders before it even hits local systems. What essential take-home message would you want the public to remember from this research? Aircraft wastewater surveillance provides a non-invasive, cost-effective, and scalable method for detecting AMR and emerging pathogens before they enter local systems. By analysing wastewater from flights, we can gain early insights into global holistic health threats. This approach complements existing surveillance systems and has the potential to become a key component of our public well-being toolkit in the fight against AMR and future pandemics. ********************************************************************************************************* Other gems to explore from the blog: What is the link between COVID boosters and Influenza-like Illness? A surprising finding that deserves further scrutiny Preaching to the Choir Leaves the Town Cold