Metabolomic analysis of breath samples for pneumonia detection

A UK research project has discovered a potential new breath test for pneumonia. The collaborative study involved scientists from the University of Manchester, the University Hospital of South Manchester NHS Foundation Trust and the Salford Royal NHS Foundation Trust (all UK). Their findings were published in Thorax earlier this year.

Patients in critical care can be susceptible to developing respiratory tract infections, including ventilator-associated pneumonia. Though these infections can be treated with antibiotics, they are often difficult to diagnose. This can lead to the treatment of any patients displaying infection related symptoms with a broad spectrum antibiotic. However, as this may not always be needed, this could lead to unnecessary draining of NHS resources, and seeding antibiotic resistance.

Laboratory tests of lung samples are currently required for confirming infections, which can take days. The research team aimed to develop a new approach to diagnosing infections in critically ill patients by demonstrating that breath volatile profiles were associated with the presence of clinically relevant pathogens in the lower respiratory tract.

The researchers took samples from 46 patients with sterile brain injury requiring intubation and ventilation on the intensive care unit. The team recorded clinical and breath data three times a week from admission of the patient up to a maximum of 10 days. Breath samples were analyzed by thermal-desorption, GC and time-of-flight MS. When they then analyzed these data, a clear difference was seen between breath profiles at each time point by the presence or absence of pathogens in the respiratory tract.

The research team hopes that these findings could lead to a fast and non-invasive point-of-care monitoring and diagnostic system for lower respiratory tract infections in critically ill patients. Roy Goodacre, Professor in the School of Chemistry at The University of Manchester and one of the study authors, commented on the scope of the research: “In the setting of complex clinical questions, this innovative project highlights how the application of state-of-the-art chemical analysis and bioinformatics can provide opportunities to deliver patient safety and improve human health on a global scale.”

Sources: Fowler SJ, Basanta-Sanchez M, Xu Y, Goodacre R, Dark PM. Surveillance for lower airway pathogens in mechanically ventilated patients by metabolomic analysis of exhaled breath: a case-control study. Thorax 70(4), 320–325 (2015); New breath test for pneumonia.