Pneumonia can be caused by infection from viruses — but also from bacteria. In fact, there are over 30 ways a person can end up suffering for pneumonia. Oftentimes, figuring out the source of the problem isn’t easy, and pneumonia infection caused by different sources requires different types of treatment. To simplify this process, a team of scientists from MIT and Stanford University has developed a nanosensor that can easily determine if pneumonia diagnosed in a person is bacterial or viral.  

If a patient suffering from viral pneumonia is given medicines for bacterial infection or vice versa, their condition can deteriorate as the treatment is not effective. This new medical technology would allow doctors decide on better and more effective treatment strategies for different pneumonia patients. Currently, due to the lack of an easily applicable process to identify the type of pneumonia infection, many patients receive a treatment that is not very useful for their condition.

“The challenge is that there are a lot of different pathogens that can lead to different kinds of pneumonia, and even with the most extensive and advanced testing, the specific pathogen causing someone’s disease can’t be identified in about half of patients. And if you treat viral pneumonia with antibiotics, then you could be contributing to antibiotic resistance, which is a big problem, and the patient won’t get better,” said Sangeeta Bhatia, senior author of the study and Professor of Health Sciences at MIT.

How does the nanosensor technology work?

The researchers at MIT studied the human immune response to different types of pneumonia infections and noticed that the activity of the protease enzymes can play an important role in finding the microbe responsible for pneumonia in a person. There are more than 500 types of protease enzymes in humans. They break down protein into amino acids and facilitate processes such as cell division, DNA replication, protein recycling, blood clotting, and immune response.

Proteases are linked to the action of natural killer cells, T-cells, and neutrophils — key defenders that fight to protect the body from different pneumonia-causing pathogens. Purvesh Khatri, one of the authors of the study discovered 39 protease enzymes connected to pneumonia. Using the genetic information collected by Khatri for identifying the proteases, Bhatia et al further developed 20 nanosensors capable of interacting with the 39 different enzymes.

Each nanosensor has a peptide coating marked with a reporter molecule. Every time a protease interacts with the peptides, the related reporter molecule gets released and comes out of the body with the urine. By further examining the urine, researchers can find out the protease that interacted with the peptide and eventually identify the microbe type (bacterial or viral) responsible for pneumonia.  

The researcher at MIT tested their nanosensors on mice and during their experiment, they also observed that protease enzymes from T-cells and natural killer cells were mostly linked to viral pneumonia. Whereas the enzyme activity related to neutrophils served as an indicator of bacterial pneumonia. 

This can make pneumonia treatment more effective

Interestingly, the researchers have also employed machine learning to analyze the data from tested mice urine samples and then taught algorithms how to differentiate between viral and bacterial pneumonia infections. Now, the scientists aim to create more powerful algorithms that could also reveal the class of pathogen causing bacterial pneumonia. This would allow the doctors to prescribe the most effective antibiotic treatment to the patients.

They are also planning to develop a device similar to an asthma inhaler to inject and test the nanosensors in humans. They performed the mice experiments by placing the sensors in the windpipe of the animals. The researchers also hope that in the future, urine tests could be conducted on paper strips, making pneumonia detection a very accessible and easy process.

Pneumonia is responsible for about two million deaths annually and disproportionately affects children below the age of five; in 2017, it killed more than 800,000 children across the globe. One of the primary reasons that make pneumonia so deadly is the confusion associated with the type of pathogen that causes it — developing a sensor (especially a cheap and easily available sensor) that could help doctors make the distinction could save many lives. 

The nanosensor technology sounds like a promising solution to this serious problem, let’s hope the researcher’s experiments turn out to be a success in the case of humans as well.   

The study is published in the journal Proceedings of the National Academy of Sciences.