More than 20 million patients a year across the world develop respiratory failure and need mechanical ventilation in critical care units.
Up to 1 in 5 of these patients are at risk of developing potentially life-threatening secondary lung infections – ventilator-associated pneumonia.
Now a new research study aims to improve testing for these infections so they can be diagnosed quickly and reliably. That will help doctors decide which patients need antibiotic treatment, which ones to use and when to stop them.
Salford Royal is one just four UK sites taking part in the BAC2BAC study, which is led by the University of Edinburgh and Lothian Health Board and funded by the Wellcome Trust. Dr Richard O’Sullivan (above left) is to lead the work at Salford, where he is a doctoral clinical research fellow. Critical care consultant Professor Paul Dark (above right) is co-principal investigator.
The study involves passing a new technology – a very fine microscope called an optical molecular alveoscope – into air sacs at the bottom of the lungs and delivering tiny amounts of highly sensitive and selective fluorescent dyes which light up when they contact specific bacteria or inflammatory cells. Researchers will also take small samples from those areas to determine the bacteria present and tailor the choice of antibiotics more quickly.
Precautionary approach
Dr O’Sullivan said. “Currently, we don’t have beside tests that can quickly and reliably diagnose lung infections in patients on ventilators and often rely on vague chest X-ray changes or abnormalities in blood. We collect samples of fluid from the lung and send these to the lab to culture, but results can take 48-72 hours.”.
“It means we have to take a precautionary approach, treating patients with broad spectrum antibiotics when they may not need them or they may be the wrong antibiotics for the type of infection they have. Safely decreasing the use of antibiotics is key to tackling the development of antibiotic resistance, one of the biggest public health threats we face.
“The hope is that this new technology will bring the lab to the lung,and potentially the ability to diagnose infection in real-time.”
The study aims to recruit 225 adult patients and will focus on those needing mechanical ventilation and where doctors suspect infection.
International challenge
Dr O’Sullivan added: “In the past, we used to think the lungs were a sterile space but there’s now evidence that, like the gut, they actually contain beneficial and harmful bacteria. This technology could potentially help us profile the lung microbiome, improving our understanding and making diagnosis and treatment more precise.”
Professor Dark said: “Developing and testing new technologies aimed at the best use of antibiotics for critically ill patients is an international challenge and links directly to improvements in patient safety and reducing downstream antimicrobial resistance (AMR) pressures. In an established partnership with NIHR Manchester BRC Respiratory Medicine theme and Professor Tim Felton, we are delighted to be progressing this leading research to include and benefit patients in Greater Manchester.”