October 15, 2024 | As the departments of Defense and Homeland Security are acutely aware, national security and human health have a lot of crossover, including biothreats and infectious diseases. Their investment in instrumentation for rapid analysis of biologic aerosols in the late 1990s is now being creatively repurposed by engineers at Zeteo Tech, together with some novel breath sampling techniques, for the early detection of respiratory infections.
The first stop is the intensive care unit (ICU), where physicians closely monitor patents for lower respiratory tract infection (LRTIs), according to Michael McLoughlin, vice president of research. Patient outcomes from LRTIs generally improve when antibiotics are given early. But diagnosing LRTIs is notoriously difficult so it can easily be treated unnecessarily or with the wrong drug, inadvertently adding to the antimicrobial crisis.
Zeteo has stepped in with a breath test system, known as BreathBiomics, which could be integrated with either a mechanical ventilator or face mask to detect human neutrophil elastase (HNE), a biomarker of LRTIs such as bronchitis and pneumonia. In a recent proof-of-concept study, led by Zeteo’s Director of Biomedical Programs Dapeng Chen, Ph.D., and published recently in PNAS Nexus (DOI: 10.1093/pnasnexus/pgae350), the diagnostic potential of the in vitro assay was demonstrated on breath samples collected from intubated patients and healthy volunteers.
In the clinic, the difficulty for physicians is distinguishing colonization from infection since the presence of bacteria alone doesn’t necessarily mean active disease, McLoughlin says. In South Africa, the rampant transmission of tuberculosis (TB) is caused by the active cases that are often not spotted until patients have a fever and their white blood cell count is elevated. The disease is by then often incurable and has unknowingly spread to others.
As with the ICU patients on mechanical ventilation, early detection is key. To that end, one of Zeteo Tech’s first projects after it launched a decade ago was to understand how TB propagates. The work, then funded by the Bill & Melinda Gates Foundation, is now supported by the National Institutes of Health.
The focus of the new assay is the host response—specifically, proteases in the immune system that multiply when there’s an infection, says McLoughlin. In the case of LRTIs, the most tightly correlated protease is HNE. “Its presence is indicative of not just a general inflammation response, but the fact that you have a lung infection.”
The Zeteo team is now looking at other proteases to gain more information about the nature of the infection, he adds. They are particularly interested in differentiating bacterial and viral infections, which could further aid antimicrobial stewardship efforts in and outside the ICU.
The BreathBiomics system may well work on its own as well as with complimentary tests, McLoughlin says. One of its key advantages will be its lower cost relative to PCR-based respiratory panels, enabling testing that could be done every day, much like a blood draw, to look for markers of infection and perhaps the specific causal bacteria. The system won’t necessarily supplant PCR testing but might allow physicians to begin the diagnostic process earlier to “get ahead of the infection.”
Integral to the overall vision is Zeteo’s core matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) technology, named digitalMALDI, initially developed with grant support from the Defense Advanced Research Projects Agency, which screens for biothreats without the culturing step. It’s a high-resolution mass spectrometer yet the size of a briefcase and battery-powered, he says.
Initially, digitalMALDI will be deployed in hospitals, but ultimately could be sitting in a doctor’s office or in the hands of emergency crews in the field, such as the first responders in Asheville in the aftermath of Hurricane Helene checking people for infections due to contaminated water, continues McLoughlin. Proteases also aren’t the only kind of biomolecule that can be captured for analysis from breath.
BreathBiomics has high affinity for a diverse range of lipids, metabolites, and proteins contained within submicron particles, which allows for a thorough and accurate assessment of respiratory health, he says. The system can be tailored for the targeted collection of biomarkers and could potentially integrate with respiratory devices such as face masks, mouthpieces, oxygen masks, incubators, and tracheostomy tubes as well as mechanical ventilators.
As a sample collection technique, BreathBiomics also compares favorably to bronchoalveolar lavage (BAL), which involves shooting fluid into the lungs and then suctioning it back out, says McLoughlin. Doctors prefer not to do BAL since it is highly invasive unless patients are “really sick,” so being able to offer a simple, low-risk system in those scenarios should be quite impactful, he adds.
If simple face masks are interfaced with the BreathBiomics system, self-testing at home could become a reality since the collected samples are highly stable even after a few months in a regular refrigerator, says McLoughlin. People could mail in their sample knowing the assay would return a reliable result.
In hurricane-ravaged regions and on the battlefield, freezers won’t necessarily be readily available for storing samples if they can’t be immediately analyzed, he points out.
McLoughlin and his colleagues had an informational session with the U.S. Food and Drug Administration earlier this year and recently subsequently sent in a request for feedback through the agency’s Pre-Submission Program. They hope that regulatory clearance of the BreathBiomics system can happen through the 510(k) regulatory pathway, which will mean a quicker time to market than the more in-depth Premarket Approval route, he says.
Since several members of the Zeteo team (McLoughlin included) hail from the Johns Hopkins University Applied Physics Laboratory, they’ve been working with four affiliated ICUs in the Baltimore region, he reports. They also just established a collaboration with the University of Pittsburgh Medical Center and Oregon Health & Science University, while research continues in South Africa via an academic partner at the University of Cape Town.
The BreathBiomics technology may well have clinical utility in ways yet to be imagined, McLoughlin says. “We’re good as technologists, but we don’t always know what the applications are. This whole thing started because a doctor came to us and said he had a problem.”
Other solutions developed by Zeteo Tech similarly happened in response to a customer request, with a fair amount of support from the federally funded Small Business Innovation Research program, he points out. Exhibit A is a canine hearing protection system for military dogs exposed to high noise levels, inhibiting their ability to respond to verbal commands—now out-licensed and sold commercially (Rex Specs Ear Pro). It didn’t hurt that McLoughlin had prior experience in the hearing protection field.
That Zeteo Tech also has an in-vehicle occupant detection system reflects a concern of President and CEO Wayne Bryden about children dying in hot cars, McLoughlin says. The system, developed with funding from the U.S. Department of Transportation, combines front- and rear-camera modules and environmental sensors to assess driver and passenger behavior and detect unattended children and pets. Its targets currently are school and public transit buses and self- and assisted-driving vehicles.