When people discuss aircraft wastewater surveillance, they almost always mean viruses: SARS-CoV-2, influenza, RSV, Mpox. These are the pathogens that dominate the headlines and motivate most of the current research. But a 2025 study in Microbiology Spectrum introduced a different — and in some ways more concerning — dimension to the picture: antimicrobial resistance.

The other pandemic threat

Antimicrobial resistance (AMR) is the process by which bacteria, fungi, parasites, and viruses evolve to defeat the drugs designed to kill them. The World Health Organization has described it as one of the greatest threats to global health, food security, and development. In 2019, drug-resistant infections were directly responsible for 1.27 million deaths worldwide and contributed to nearly 5 million more. By 2050, AMR is projected to cause 10 million deaths annually — more than cancer [1].

What makes AMR different from pandemic viruses is how it spreads. Viruses spread person to person through respiratory droplets, close contact, or surfaces. Resistance genes spread differently — they spread through the movement of bacteria and, crucially, through the horizontal transfer of genetic material between bacteria in shared environments. Wherever humans and their gut microbiomes travel, resistance genes travel with them.

The aircraft lavatory as a resistance gene repository

Ahmed and colleagues published a proof-of-concept study in 2025 demonstrating that aircraft lavatory wastewater from long-haul flights contains detectable AMR genes [2]. The lavatory holding tank of a 12-hour flight, they found, functions as a concentrated repository of the intestinal microbiomes of hundreds of passengers from potentially dozens of countries — including any resistance genes those microbiomes carry.

What the study specifically found:

  • Carbapenem resistance genes — including variants of the NDM (New Delhi Metallo-beta-lactamase) enzyme — were detectable in aircraft wastewater samples. Carbapenem-resistant bacteria are among the most dangerous in clinical settings because carbapenems are the antibiotics of last resort; when a bacterium resists them, treatment options collapse.
  • ESBL (extended-spectrum beta-lactamase) genes — which confer resistance to most penicillins and cephalosporins — were present.
  • mcr genes — which encode colistin resistance, another last-resort antibiotic — were also identified.

These are not exotic findings in clinical settings. Carbapenem-resistant Klebsiella and NDM-producing E. coli are already global problems. What aircraft wastewater surveillance reveals is the movement of these genes — which corridors they travel, which regions are exporting resistance to which destinations.

Why this matters differently from viral surveillance

With viral pathogens, the question is: "Is this variant crossing our border?" With AMR, the question is subtler: "Which resistance genes are arriving, from where, and at what frequency?"

The clinical consequence may not be immediate. A traveler carrying NDM-producing bacteria in their gut may never develop an infection. But they shed those bacteria — and their genes — into the shared environment. In a hospital setting, those genes can transfer horizontally to other bacteria. In a community setting, they spread through environmental routes. The individual traveler is asymptomatic; the global resistance landscape shifts.

A virus causes an outbreak you can see. A resistance gene causes a future clinical crisis you cannot trace back to any single source. Aircraft wastewater surveillance changes that by creating a record of origin, corridor, and frequency.

Building AMR into the aircraft wastewater panel

The technical case for including AMR gene detection in aircraft wastewater programs is strong. The same wastewater sample processed for SARS-CoV-2 and influenza PCR can be simultaneously analyzed for AMR gene panels using multiplex qPCR or shotgun metagenomic sequencing. The marginal cost of adding AMR detection to an existing wastewater program is substantially lower than building a standalone AMR surveillance system.

For Thailand specifically, this is relevant in multiple ways. The country receives international travelers from regions with high AMR prevalence — parts of South Asia, Southeast Asia, and East Africa where NDM-producing and carbapenem-resistant organisms are endemic. Suvarnabhumi's route map is, in AMR terms, a map of resistance gene importation risk.

An AWSS panel that includes AMR detection gives the Department of Disease Control and the Ministry of Public Health a real-time readout of which resistance genes are arriving and from which corridors — data that currently does not exist in any systematic, border-level form anywhere in Southeast Asia.

This is not a distant ambition. The proof-of-concept is published. The methodology is validated. The next step is operational integration.