Scientists and doctors at the University of Cambridge and Cambridge University Hospitals NHS Foundation Trust have developed a simple DNA test to identify secondary infections in COVID-19 patients with severe COVID-19 quickly. The newly developed test gives doctors the information they need to start treatment within hours rather than days.
Based on higher throughput DNA testing, the approach is a step towards better treatment for infection more generally.
Co-author Dr. Andrew Conway Morris from Cambridge’s Department of Medicine and an intensive care consultant said, “Early on in the pandemic we noticed that COVID-19 patients appeared to be particularly at risk of developing secondary pneumonia, and started using a rapid diagnostic test that we had developed for just such a situation. Using this test, we found that patients with COVID-19 were twice as likely to develop secondary pneumonia as other patients in the same intensive care unit.”
Normally, confirming a pneumonia analysis is trying, as bacterial samples from patients should be refined and filled in a lab, which is tedious. The Cambridge test adopts an elective strategy by detecting different pathogens’ DNA, which allows for faster and more accurate testing.
Morris said, “The test uses multiple polymerase chain reaction (PCR) which detects the DNA of the bacteria and can be done in around four hours, meaning there is no need to wait for the bacteria to grow. Often, patients have already started to receive antibiotics before the bacteria have had time to grow in the lab. This means that results from cultures are often negative, whereas PCR doesn’t need viable bacteria to detect – making this a more accurate test.”
“The test runs multiple PCR reactions in parallel and can simultaneously pick up 52 different pathogens, which often infect the lungs of patients in intensive care. At the same time, it can also test for antibiotic resistance.”
Lead author Mailis Maes, also from the Department of Medicine, said, “We found that although patients with COVID-19 were more likely to develop secondary pneumonia, the bacteria that caused these infections were similar to those in ICU patients without COVID-19.”
This study was funded by the National Institute for Health Research Cambridge Biomedical Research Centre.
- Mailis Maes et al. ‘Ventilator-associated pneumonia in critically ill patients with COVID-19.’ Critical Care, (2021). DOI: 10.1186/s13054-021-03460-5