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Fluorescent imaging probe quickly detects gram-negative bacteria in lungs
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Researchers developed a fluorescent imaging probe that can visualize gram-negative bacteria in human lungs in real time and reported that it was safe, practical and effective in detecting infections in a proof-of-concept study.
Writing in Science Translational Medicine, Ahsan R. Akram, MBChB, PhD, a clinician scientist fellow with Cancer Research UK and honorary consultant in respiratory medicine at the University of Edinburgh, and colleagues noted the challenges in accurately and rapidly diagnosing gram-negative pneumonia. Biopsy and culture is the current gold standard, they explained, but comes with safety concerns, notably in mechanically ventilated patients, who are especially vulnerable to hospital-acquired gram-negative bacterial infections.
“The clinical suspicion of nosocomial pneumonia is highly sensitive, often leading to inappropriate and/or overtreatment with broad-spectrum antimicrobial therapy,” Akram and colleagues wrote. “Current approaches to guide antimicrobial therapy for suspected pneumonia rely on the growth of bacteria from aspirated fluids or expectorated samples along with antimicrobial susceptibility testing.”
The researchers developed a topically administered imaging probe consisting of a fluorescent molecule attached to a polymyxin, which bind to gram-negative bacteria, that can then be visualized using optical endomicroscopy (OEM).
They tested the approach in six patients with bronchiectasis and seven mechanically ventilated critically ill ICU patients with suspected pneumonia. According to the study, the method was able to quickly and accurately track gram-negative bacteria in patients, demonstrating its capability as a diagnostic and monitoring tool and a potential way to reduce the inappropriate use of antibiotics.
Akram and colleagues reported that the technology is not toxic and did not cause any major adverse events. They said further research is needed to determine if there is a risk associated with repeated use.
“High-resolution OEM coupled with a fluorescent probe was able to delineate bacterial presence in distinct segments of the pulmonary tree (such as the acinar gas–exchanging unit) and associated imaging parameters such as cellular infiltrates,” Akram and colleagues wrote. “The specificity, safety, and rapid readout of this technology platform represent potentially significant advantages over current technologies and now require further large-scale validation.” – by Marley Ghizzone
Disclosures: Akram reports receiving travel fees for attendance at educational conferences supported by an unrestricted educational grant from Mauna Kea Technologies. Please see the study for all other authors’ relevant financial disclosures.
Perspective
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Technologies such as these that detect the presence or absence of potential pathogenic bacteria rapidly have important implications for treatment and stewardship. This technology might be used by clinicians to decide whether a patient has bacterial pneumonia and whether a broad-spectrum antibiotic needs to be administered. These types of technologies which provide real-time, point-of-care results regarding the presence or absence of potential pathogens are very important and inform important therapeutic and stewardship interventions and decisions. This technology would need to be studied in real-world clinical settings, and processes would need to be implemented to make certain the results were interpreted appropriately and to evaluate how results impacted clinical care.
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