Researchers develop drive-thru-type test to detect viral infections in bacteria

The pandemic has highlighted the threat that certain viruses pose to humans. But viruses can also infect vital bacteria, and a team led by Johns Hopkins University has developed a test to determine if the bacteria are sick, similar to the one used to test humans for COVID-19.

“If there was a COVID-like pandemic in large bacterial populations, it would be difficult to say, because prior to this study, we lacked the affordable and accurate tools needed to study viral infections in uncultured bacterial populations,” said corresponding study author Sarah Preheim. , Johns Hopkins Assistant Professor of Environmental Health and Engineering.

The results were published today in Microbiology of nature.

The diseased bacteria are blocked in their function as decomposers and as part of the foundation of the food web in Chesapeake Bay and other waterways. Determining viral infections in bacteria has traditionally relied on growing both bacteria and viruses, which is missing 99% of bacteria found in the environment because they cannot be grown in culture, Preheim says, adding that Testing for viral infections on uncultured bacteria is expensive and difficult to apply widely, much like the early stages of the COVID-19 test.

The key to making testing for viral infections for uncultured bacteria faster and more affordable was to isolate single bacterial cells in a small bubble (i.e., an emulsion droplet) and merge the genes virus and bacteria once inside.

“The fused genes act as name tags for bacteria and viruses,” said lead author Eric Sakowski, a former postdoctoral researcher at the Preheim lab who is now an assistant professor at Mount St. Mary’s University. “By merging the genes together, we are able to identify which bacteria are infected, as well as which variant of the virus is causing the infection.”

The resulting test provides a new way to screen for viral infections in a subset of bacterial populations. The test allows researchers to identify a link between environmental conditions and infections in Actinobacteria, one of the most abundant bacterial groups in the Chesapeake Berry and which plays a crucial role in breaking down organic matter, making them nutrients available to plants and photosynthetic algae.

Although the researchers developed this tool to study Chesapeake Bay, they say their approach could be widely applied in aquatic ecosystems, shedding light on viral ecology and helping predict – and even prevent – devastating environmental impacts.

“This testing tool makes it easier for us to track viral infections, so that we can monitor these infections to see when they are most likely to have significant environmental consequences,” said Preheim.

Sakowski said the new test may one day also affect how we deal with bacterial infections.

“Viruses have the potential to treat infections caused by bacteria resistant to antibiotics,” he said. “Knowing which viruses most effectively infect bacteria will be essential for this type of treatment.”