Current Analytical Methods and Challenges for the Clinical Diagnosis of Invasive Pulmonary Aspergillosis Infection

Abstract

In the last decade, pulmonary fungal infections such as invasive pulmonary aspergillosis (IPA) have increased in incidence due to the increased number of immunocompromised individuals. This increase is especially problematic when considering mortality rates associated with IPA are upwards of 70%. This high mortality rate is due to, in part, the length of time it takes to diagnose a patient with IPA. When diagnosed early, mortality rates of IPA decrease by as much as 30%. In this review, we discuss current technologies employed in both medical and research laboratories to diagnose IPA, including culture, imaging, polymerase chain reaction, peptide nucleic acid-fluorescence in situ hybridization, enzyme-linked immunosorbent assay, lateral flow assay, and liquid chromatography mass spectrometry. For each technique, we discuss both promising results and potential areas for improvement that would lead to decreased diagnosis time for patients suspected of contracting IPA. Further study into methods that offer increased speed and both analytical and clinical sensitivity to decrease diagnosis time for IPA is warranted.

Keywords: diagnosis; enzyme-linked immunosorbent assay; high-pressure liquid chromatography mass spectrometry; invasive pulmonary aspergillosis; peptide nucleic acid–fluorescence in situ hybridization; polymerase chain reaction.

Figure 1

Generic structure of Aspergillosis sp.

Figure 2

General scheme for sandwich ELISA signal detections—an antigen is added to an antibody captured on the surface of the ELISA. Then, a labeled antibody is added. When the molecule of interest (substrate) is added to the labeled antibody, a signal is produced.

Figure 3

General schematic for PNA-FISH. First, the cell undergoes permeabilization and the RNA is fixated. Second, the target RNA is hybridized with the PNA probe. Third, excess probes are washed from the cells. Finally, the cells are detected using epifluorescence microscopy.