The IRIDICA PCR/Electrospray Ionization-Mass Spectrometry Assay on Bronchoalveolar Lavage for Bacterial Etiology in Mechanically Ventilated Patients with Suspected Pneumonia

• Published in: PloS one Vol. 11; no. 7; p. e0159694
• Main Authors: Strålin, Kristoffer, Ehn, Fredrik, Giske, Christian G, Ullberg, Måns, Hedlund, Jonas, Petersson, Johan, Spindler, Carl, Özenci, Volkan
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 27.07.2016; Public Library of Science (PLoS)
• Subjects: Alveoli; Antibiotics; Bacteria; Biology and Life Sciences; Bronchoalveolar lavage; Bronchoalveolar Lavage Fluid - microbiology; Bronchus; Case-Control Studies; Causes of; Chemical properties; Complications and side effects; Confidence intervals; Culture; Deoxyribonucleic acid; Development and progression; Diagnosis; Diagnostic systems; DNA; Electrospraying; Etiology; Humans; Infectious diseases; Intensive care; Ionization; Laboratories; Mass spectrometry; Mass spectroscopy; Mechanical ventilation; Medicin och hälsovetenskap; Medicine; Medicine and Health Sciences; Methods; Microbiology; Molecular Diagnostic Techniques - methods; Pathogens; Patients; Pneumonia; Pneumonia - microbiology; Pneumonia - pathology; Pneumonia - therapy; Polymerase chain reaction; Polymerase Chain Reaction - methods; Research and Analysis Methods; Respiration, Artificial; Scientific imaging; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization - methods; Spectroscopy; Staphylococcus infections; Streptococcus infections; Studies; Ventilation; Ventilators; Sweden; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0159694

We studied the diagnostic performance of the IRIDICA PCR/electrospray ionization-mass spectrometry (PCR/ESI-MS) assay applied on bronchoalveolar lavage (BAL) samples, from 51 mechanically ventilated patients with suspected pneumonia, in a prospective study. In 32 patients with X-ray verified pneumonia, PCR/ESI-MS was positive in 66% and BAL culture was positive in 38% (p = 0.045), and either of the methods was positive in 69%. The following BAL result combinations were noted: PCR/ESI-MS+/culture+, 34%; PCR/ESI-MS+/culture-, 31%; PCR/ESI-MS-/culture+, 3.1%; PCR/ESI-MS-/culture-, 31%; kappa 0.36 (95% confidence interval (CI), 0.10-0.63). In pneumonia patients without prior antibiotic treatment, optimal agreement was noted with 88% PCR/ESI-MS+/culture+ and 12% PCR/ESI-MS-/culture- (kappa 1.0). However, in patients with prior antibiotic treatment, the test agreement was poor (kappa 0.16; 95% CI, -0.10-0.44), as 10 patients were PCR/ESI-MS+/culture-. In 8/10 patients the pathogens detected by PCR/ESI-MS could be detected by other conventional tests or PCR tests on BAL. Compared with BAL culture, PCR/ESI-MS showed specificities and negative predictive values of ≥87% for all individual pathogens, an overall sensitivity of 77% and positive predictive value (PPV) of 42%. When other conventional tests and PCR tests were added to the reference standard, the overall PPV increased to 87%. The PCR/ESI-MS semi-quantitative level tended to be higher for PCR/ESI-MS positive cases with pneumonia compared with cases without pneumonia (p = 0.074). In conclusion, PCR/ESI-MS applied on BAL showed a promising performance and has potential to be clinically useful in mechanically ventilated patients with suspected pneumonia. The usefulness of the method for establishment of pneumonia etiology and selection of antibiotic therapy should be further studied.