Researchers have developed a DNA test to quickly identify secondary infections in COVID-19 patients, who have double the risk of developing pneumonia while on ventilation.

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For patients with the most severe forms of COVID-19, mechanical ventilation is often the only way to keep them alive, as doctors use anti-inflammatory therapies to treat their inflamed lungs. However, these patients are susceptible to further infections from bacteria and fungi that they may acquire while in hospital -- so called 'ventilator-associated pneumonia'.

"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," said co-author Andrew Conway Morris from the University of Cambridge.

"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," Conway added. Normally, confirming a pneumonia diagnosis is challenging, as bacterial samples from patients need to be cultured and grown in a lab, which is time-consuming.

The test takes an alternative approach by detecting the DNA of different pathogens, which allows for faster and more accurate testing, according to a paper published in the journal Critical Care. 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.

IT 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. "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," said lead author Mailis Maes from the varsity. "This means that standard antibiotic protocols can be applied to COVID-19 patients," Maes added.