Detect germs in the air, room by room

What if you could stop germs at the door? Or know within minutes if a virus is present in the air?

Rush scientists are working on a tool that can detect germs in the air, even when they enter a building or gathering place. It’s one of an ongoing effort to discover ways to protect the public from infectious diseases.

Hannah Barbian, Ph.D., is a genomic epidemiologist, a scientific detective whose arsenal includes genomic sequencing of evidence—that is, germs that are known to be circulating and those that may be a surprise.

Barbian analyzes germs, maps their genomic composition, investigates outbreaks and researches emerging viral and bacterial threats at Rush’s Regional Innovative Public Health Laboratory.

She identifies and tracks COVID-19 variants for the Chicago Department of Public Health by analyzing samples shared by area hospitals. This surveillance has been an important part of the local and national public health response since the start of the pandemic.

While current surveillance programs track strains of respiratory viruses and bacteria in available patient samples, aerosol technology identifies pathogens present inside a building, room by room.

Barbian’s work inspired her to study what air sampling could accomplish, how accurate it could be, and how quickly and easily it could detect pathogens at specific locations.

So far, so good

Obtaining air samples is easy, which means this method could potentially provide real-time monitoring of germs at the room level, quickly and simply, she said.

Barbian installed an air sampler, a 13-by-14-inch box about the size of a desktop printer, in four locations at Rush University Medical Center: two in the emergency room, one in a lobby and the fourth near a hospital entrance.

In collaboration with the Chicago Department of Public Health, air sampling devices have also been placed at six other locations across Chicago to test how air sampling can complement existing disease surveillance methods. The sampling is part of RIPHL’s work to conduct pathogen genome surveillance.

“It can capture the air in a large room and, if placed strategically, for example at an entry point or in a shared lunch area, it can collect data on infectious diseases from the occupants of a building,” she said.

Barbian’s research into the new technology began as a pilot project for the Rush Center for Emerging Infectious Diseases, which selected eight projects designed to improve infectious disease research and community preparedness in Chicago.

The Aerosol Sense sampling device collects air from all directions continuously in a designated area. Testing of air samples can be completed in just one and a half hours.

Barbian looks for known respiratory viruses and bacteria while studying what’s in the air. To detect new microbes, Barbian uses a process called metagenomic sequencing, which studies the genomic makeup of any pathogens that might be found in the samples.

“Our preliminary data suggest that a large number of human bacteria and viruses can be observed in air samples,” she said.

Searching for new pathogens

The study also tested the air for eight types of respiratory viruses and bacteria known to be of concern, such as influenza. The results from the air samples were consistent with those obtained from traditional clinical surveillance, she said. Even the COVID-19 virus detected in the air matched lineages detected in clinical samples collected around the same time.

From what she’s found so far, air sampling could help identify the presence of a broad range of germs while improving current surveillance methods that analyze wastewater and clinical samples for specific viruses, she said.

“It’s easier to get air samples, and the technology provides more targeted and accurate results than wastewater,” Barbian said. “And it requires less coordination than clinical sampling.”

Although ambient air contains the genetic material of many types of germs, their presence should not be a concern to people in the areas tested. The device identifies minute amounts of viruses, and detection does not necessarily indicate the presence of a live or transmissible virus.