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DOI: 10.1055/a-2808-5317
Microbiologic Diagnosis of Respiratory Infections in Critically Ill Immunocompromised Patients
Authors
Funding Information C.P. is supported by the U.S. Department of Health and Human Services, National Institutes of Health, National Center for Advancing Translational Sciences (grant no.: 5KL2TR001424-09); U.S. Department of Health and Human Services, National Institutes of Health, National Institute of Allergy and Infectious Diseases (grant no.: U19AI135964); and U.S. Department of Health and Human Services, National Institutes of Health, National Institute on Aging (grant no.: 1R01AG078261-01A1).
Abstract
Critically ill, immunocompromised individuals are vulnerable to both common and uncommon etiologies of respiratory infection. Identifying the etiology of infection has therapeutic, prognostic, and public health implications. In some circumstances, immunocompromised patients may be empirically treated with excessively broad antibiotics but ultimately be diagnosed with a common cause of pneumonia. In other circumstances, immunocompromised patients may have a non-specific clinical presentation for severe respiratory failure and be diagnosed with a rare etiology of infection. Because this patient population is at risk for a broad array of infections, it is important to understand the advantages and limitations of sampling and diagnostic techniques. Furthermore, the last decades of research have produced novel methods to enhance diagnostic accuracy. Many of these tests are molecular diagnostics that have high sensitivity, but their clinical impact is unknown, particularly in immunocompromised individuals. In this article we discuss various approaches to sampling and microbiologic diagnosis in immunocompromised individuals with severe respiratory failure.
Publication History
Received: 03 December 2025
Accepted: 06 February 2026
Article published online:
28 February 2026
© 2026. Thieme. All rights reserved.
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References
- 1 Ramirez JA, Chandler TR, Furmanek SP. et al; Louisville CAP in the Immunocompromised Study Group. Community-acquired pneumonia in the immunocompromised host: epidemiology and outcomes. Open Forum Infect Dis 2023; 10 (11) ofad565
- 2 Murali S, Marks A, Heeger A, Dako F, Febbo J. Pneumonia in the immunocompromised host. Semin Roentgenol 2022; 57 (01) 90-104
- 3 Azoulay E, Mokart D, Kouatchet A, Demoule A, Lemiale V. Acute respiratory failure in immunocompromised adults. Lancet Respir Med 2019; 7 (02) 173-186
- 4 Di Pasquale MF, Sotgiu G, Gramegna A. et al; GLIMP Investigators. Prevalence and etiology of community-acquired pneumonia in immunocompromised patients. Clin Infect Dis 2019; 68 (09) 1482-1493
- 5 Park DE, Baggett HC, Howie SRC. et al; PERCH Study Group. Colonization density of the upper respiratory tract as a predictor of pneumonia-Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and Pneumocystis jirovecii. Clin Infect Dis 2017; 64 (Suppl. 03) S328-S336
- 6 Claassen-Weitz S, Lim KYL, Mullally C, Zar HJ, Nicol MP. The association between bacteria colonizing the upper respiratory tract and lower respiratory tract infection in young children: a systematic review and meta-analysis. Clin Microbiol Infect 2021; 27 (09) 1262-1270
- 7 Bhuiyan MU, Snelling T, Sikazwe C. et al. Nasopharyngeal density of respiratory viruses in childhood pneumonia in a highly vaccinated setting: findings from a case-control study. BMJ Open Respir Res 2020; 7 (01) e000593
- 8 Feikin DR, Fu W, Park DE. et al; PERCH Study Group. Is higher viral load in the upper respiratory tract associated with severe pneumonia? Findings from the PERCH study. Clin Infect Dis 2017; 64 (Suppl. 03) S337-S346
- 9 Bono K, Caceda JA, Zhai M. et al. Evaluating methicillin-resistant Staphylococcus aureus polymerase chain reaction nasal screening as a tool for antimicrobial stewardship. J Surg Res 2023; 283: 1047-1052
- 10 Williamson K, Bisaga A, Paquette K, Lovell E. The prevalence of methicillin-resistant Staphylococcus aureus colonization in emergency department fast track patients. World J Emerg Med 2013; 4 (04) 278-279
- 11 Bessesen MT, Kotter CV, Wagner BD. et al. MRSA colonization and the nasal microbiome in adults at high risk of colonization and infection. J Infect 2015; 71 (06) 649-657
- 12 Weiser JN, Ferreira DM, Paton JC. Streptococcus pneumoniae: transmission, colonization and invasion. Nat Rev Microbiol 2018; 16 (06) 355-367
- 13 Prendki V, Huttner B, Marti C. et al. Accuracy of comprehensive PCR analysis of nasopharyngeal and oropharyngeal swabs for CT-scan-confirmed pneumonia in elderly patients: a prospective cohort study. Clin Microbiol Infect 2019; 25 (09) 1114-1119
- 14 Lachant DJ, Croft DP, McGrane Minton H, Prasad P, Kottmann RM. Nasopharyngeal viral PCR in immunosuppressed patients and its association with virus detection in bronchoalveolar lavage by PCR. Respirology 2017; 22 (06) 1205-1211
- 15 Dumas G, Bertrand M, Lemiale V. et al. Prognosis of critically ill immunocompromised patients with virus-detected acute respiratory failure. Ann Intensive Care 2023; 13 (01) 101
- 16 Desmet T, Paepe P, Boelens J. et al. Combined oropharyngeal/nasal swab is equivalent to nasopharyngeal sampling for SARS-CoV-2 diagnostic PCR. BMC Microbiol 2021; 21 (01) 31
- 17 Budayanti NS, Suryawan K, Iswari IS, Sukrama DM. The quality of sputum specimens as a predictor of isolated bacteria from patients with lower respiratory tract infections at a tertiary referral hospital, Denpasar, Bali-Indonesia. Front Med (Lausanne) 2019; 6: 64
- 18 Markussen DL, Ebbesen M, Serigstad S. et al. The diagnostic utility of microscopic quality assessment of sputum samples in the era of rapid syndromic PCR testing. Microbiol Spectr 2023; 11 (05) e0300223
- 19 García-Vázquez E, Marcos MA, Mensa J. et al. Assessment of the usefulness of sputum culture for diagnosis of community-acquired pneumonia using the PORT predictive scoring system. Arch Intern Med 2004; 164 (16) 1807-1811
- 20 LaRocque RC, Katz JT, Perruzzi P, Baden LR. The utility of sputum induction for diagnosis of Pneumocystis pneumonia in immunocompromised patients without human immunodeficiency virus. Clin Infect Dis 2003; 37 (10) 1380-1383
- 21 Ioanas M, Ferrer R, Angrill J, Ferrer M, Torres A. Microbial investigation in ventilator-associated pneumonia. Eur Respir J 2001; 17 (04) 791-801
- 22 Burger CD. Utility of positive bronchoalveolar lavage in predicting respiratory failure after hematopoietic stem cell transplantation: a retrospective analysis. Transplant Proc 2007; 39 (05) 1623-1625
- 23 Patel NR, Lee PS, Kim JH, Weinhouse GL, Koziel H. The influence of diagnostic bronchoscopy on clinical outcomes comparing adult autologous and allogeneic bone marrow transplant patients. Chest 2005; 127 (04) 1388-1396
- 24 Dunagan DP, Baker AM, Hurd DD, Haponik EF. Bronchoscopic evaluation of pulmonary infiltrates following bone marrow transplantation. Chest 1997; 111 (01) 135-141
- 25 Shannon VR, Andersson BS, Lei X, Champlin RE, Kontoyiannis DP. Utility of early versus late fiberoptic bronchoscopy in the evaluation of new pulmonary infiltrates following hematopoietic stem cell transplantation. Bone Marrow Transplant 2010; 45 (04) 647-655
- 26 Hofmeister CC, Czerlanis C, Forsythe S, Stiff PJ. Retrospective utility of bronchoscopy after hematopoietic stem cell transplant. Bone Marrow Transplant 2006; 38 (10) 693-698
- 27 Boersma WG, Erjavec Z, van der Werf TS, de Vries-Hosper HG, Gouw AS, Manson WL. Bronchoscopic diagnosis of pulmonary infiltrates in granulocytopenic patients with hematologic malignancies: BAL versus PSB and PBAL. Respir Med 2007; 101 (02) 317-325
- 28 Peikert T, Rana S, Edell ES. Safety, diagnostic yield, and therapeutic implications of flexible bronchoscopy in patients with febrile neutropenia and pulmonary infiltrates. Mayo Clin Proc 2005; 80 (11) 1414-1420
- 29 Rañó A, Agustí C, Jimenez P. et al. Pulmonary infiltrates in non-HIV immunocompromised patients: a diagnostic approach using non-invasive and bronchoscopic procedures. Thorax 2001; 56 (05) 379-87
- 30 Azoulay E, Pickkers P, Soares M. et al; Efraim investigators and the Nine-I study group. Acute hypoxemic respiratory failure in immunocompromised patients: the Efraim multinational prospective cohort study. Intensive Care Med 2017; 43 (12) 1808-1819
- 31 Azoulay E, Mokart D, Lambert J. et al. Diagnostic strategy for hematology and oncology patients with acute respiratory failure: randomized controlled trial. Am J Respir Crit Care Med 2010; 182 (08) 1038-1046
- 32 Fagon JY, Chastre J, Wolff M. et al. Invasive and noninvasive strategies for management of suspected ventilator-associated pneumonia. A randomized trial. Ann Intern Med 2000; 132 (08) 621-630
- 33 Ruiz M, Torres A, Ewig S. et al. Noninvasive versus invasive microbial investigation in ventilator-associated pneumonia: evaluation of outcome. Am J Respir Crit Care Med 2000; 162 (01) 119-125
- 34 Canadian Critical Care Trials Group. A randomized trial of diagnostic techniques for ventilator-associated pneumonia. N Engl J Med 2006; 355 (25) 2619-2630
- 35 Glaziou P, Floyd K, Raviglione MC. Global epidemiology of tuberculosis. Semin Respir Crit Care Med 2018; 39 (03) 271-285
- 36 Kadooka C, Hira D, Tanaka Y. et al. Identification of an α-(1 → 6)-mannosyltransferase contributing to biosynthesis of the fungal-type galactomannan α-core-mannan structure in Aspergillus fumigatus. MSphere 2022; 7 (06) e00484-e22
- 37 Costachel C, Coddeville B, Latgé JP, Fontaine T. Glycosylphosphatidylinositol-anchored fungal polysaccharide in Aspergillus fumigatus. J Biol Chem 2005; 280 (48) 39835-39842
- 38 Pagano L, Caira M, Candoni A. et al. Invasive aspergillosis in patients with acute myeloid leukemia: a SEIFEM-2008 registry study. Haematologica 2010; 95 (04) 644-650
- 39 Foy PC, van Burik JA, Weisdorf DJ. Galactomannan antigen enzyme-linked immunosorbent assay for diagnosis of invasive aspergillosis after hematopoietic stem cell transplantation. Biol Blood Marrow Transplant 2007; 13 (04) 440-443
- 40 Beirão F, Araujo R. State of the art diagnostic of mold diseases: a practical guide for clinicians. Eur J Clin Microbiol Infect Dis 2013; 32 (01) 3-9
- 41 Aydin S, Emre E, Ugur K. et al. An overview of ELISA: a review and update on best laboratory practices for quantifying peptides and proteins in biological fluids. J Int Med Res 2025; 53 (02) 3000605251315913
- 42 Schuetz AN. Invasive fungal infections: biomarkers and molecular approaches to diagnosis. Clin Lab Med 2013; 33 (03) 505-525
- 43 Mercier T, Castagnola E, Marr KA, Wheat LJ, Verweij PE, Maertens JA. Defining galactomannan positivity in the updated EORTC/MSGERC consensus definitions of invasive fungal diseases. Clin Infect Dis 2021; 72 (Suppl. 02) S89-S94
- 44 Bassetti M, Azoulay E, Kullberg BJ. et al. EORTC/MSGERC definitions of invasive fungal diseases: summary of activities of the intensive care unit working group. Clin Infect Dis 2021; 72 (Suppl. 02) S121-S127
- 45 Donnelly JP, Chen SC, Kauffman CA. et al. Revision and update of the consensus definitions of invasive fungal disease from the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium. Clin Infect Dis 2020; 71 (06) 1367-1376
- 46 Leeflang MM, Debets-Ossenkopp YJ, Wang J. et al. Galactomannan detection for invasive aspergillosis in immunocompromised patients. Cochrane Database Syst Rev 2015; 2015 (12) CD007394
- 47 Prosty C, Luo OD, Khalaf R, Del Corpo O, McDonald EG, Lee TC. Diagnostic test accuracy of the Fungitell serum (1→3)-β-D-glucan assay for the diagnosis of Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis. Clin Microbiol Infect 2025; 31 (04) 542-550
- 48 Del Corpo O, Butler-Laporte G, Sheppard DC, Cheng MP, McDonald EG, Lee TC. Diagnostic accuracy of serum (1-3)-β-D-glucan for Pneumocystis jirovecii pneumonia: a systematic review and meta-analysis. Clin Microbiol Infect 2020; 26 (09) 1137-1143
- 49 Choe PG, Kang YM, Kim G. et al. Diagnostic value of direct fluorescence antibody staining for detecting Pneumocystis jirovecii in expectorated sputum from patients with HIV infection. Med Mycol 2014; 52 (03) 326-330
- 50 Caliendo AM, Hewitt PL, Allega JM, Keen A, Ruoff KL, Ferraro MJ. Performance of a PCR assay for detection of Pneumocystis carinii from respiratory specimens. J Clin Microbiol 1998; 36 (04) 979-982
- 51 Nanayakkara D, Tegtmeier B, Ross JA. et al. 984. Diagnostic utility of bronchoalveolar lavage Pneumocystis jirovecii DNA polymerase chain reaction assay in patients with hematological malignancies and hematopoietic cell transplantation. Open Forum Infect Dis 2021; 8 (Suppl. 01) S583-S583
- 52 Lee FY, Mossad SB, Adal KA. Pulmonary mucormycosis: the last 30 years. Arch Intern Med 1999; 159 (12) 1301-1309
- 53 Hammer MM, Madan R, Hatabu H. Pulmonary mucormycosis: radiologic features at presentation and over time. AJR Am J Roentgenol 2018; 210 (04) 742-747
- 54 Fernandez JF, Maselli DJ, Simpson T, Restrepo MI. Pulmonary mucormycosis: what is the best strategy for therapy?. Respir Care 2013; 58 (05) e60-e63
- 55 Millon L, Caillot D, Berceanu A. et al. Evaluation of serum Mucorales polymerase chain reaction (PCR) for the diagnosis of mucormycoses: the MODIMUCOR prospective trial. Clin Infect Dis 2022; 75 (05) 777-785
- 56 Xu R, Li D, Zhao J. et al. Rapid detection of Mucorales based on recombinase polymerase amplification and real-time PCR. Front Microbiol 2023; 14: 1273073
- 57 Rousselot J, Millon L, Scherer E. et al. Detection of Mucorales antigen in bronchoalveolar lavage samples using a newly developed lateral-flow device. J Clin Microbiol 2025; 63 (07) e0022625
- 58 Evans SE, Jennerich AL, Azar MM. et al. Nucleic acid-based testing for noninfluenza viral pathogens in adults with suspected community-acquired pneumonia. An official American Thoracic Society Clinical Practice Guideline. Am J Respir Crit Care Med 2021; 203 (09) 1070-1087
- 59 Roży A, Duk K, Szumna B, Skrońska P, Gawryluk D, Chorostowska-Wynimko J. Effectiveness of PCR and immunofluorescence techniques for detecting human cytomegalovirus in blood and bronchoalveolar lavage fluid. Adv Exp Med Biol 2016; 921: 21-26
- 60 Boeckh M, Stevens-Ayers T, Travi G. et al. Cytomegalovirus (CMV) DNA quantitation in bronchoalveolar lavage fluid from hematopoietic stem cell transplant recipients with CMV pneumonia. J Infect Dis 2017; 215 (10) 1514-1522
- 61 Luzzati R, D'Agaro P, Busca A. et al. Herpes simplex virus (HSV) pneumonia in the non-ventilated immunocompromised host: burden and predictors. J Infect 2019; 78 (02) 127-133
- 62 Cowl CT, Prakash UB, Shawn Mitchell P, Migden MR. Varicella-zoster virus detection by polymerase chain reaction using bronchoalveolar lavage specimens. Am J Respir Crit Care Med 2000; 162 (2 Pt 1): 753-754
- 63 Al-Tawfiq JA, Kim H, Memish ZA. Parasitic lung diseases. Eur Respir Rev 2022; 31 (166) 220093
- 64 Pérez-Arellano JL, Andrade MA, López-Abán J, Carranza C, Muro A. [Helminths and the respiratory system]. Arch Bronconeumol 2006; 42 (02) 81-91
- 65 Contier J, Platon L, Benchabane N. et al. Diagnostic performance of Pneumonia multiplex PCR in critically ill immunocompromised patients. Crit Care 2025; 29 (01) 310
- 66 Affolter K, Schumann DM, Tamm M. et al. Multiplex PCR on the bronchoalveolar lavage fluid of immunocompromised patients. Chest 2018; 154 (03) 722-725
- 67 Srivastava P, Prasad D. Isothermal nucleic acid amplification and its uses in modern diagnostic technologies. 3 Biotech 2023; 13 (06) 200
- 68 Wei S, Wang L, Shi M. et al. Rapid, accurate, and novel diagnostic technique for respiratory pathogens: clinical application of loop-mediated isothermal amplification assay in older patients with pneumonia, a multicenter prospective observational study. Front Microbiol 2022; 13: 1048997
- 69 Singh P, Singh S, Mirdha BR, Guleria R, Agarwal SK, Mohan A. Evaluation of loop-mediated isothermal amplification assay for the detection of Pneumocystis jirovecii in immunocompromised patients. Mol Biol Int 2015; 2015: 819091
- 70 Scharmann U, Kirchhoff L, Buer J. et al. Evaluation of the loop-mediated isothermal amplification assay (LAMP) Eazyplex® Pneumocystis jirovecii . J Fungi (Basel) 2025; 11 (04) 300
- 71 Yigci D, Atçeken N, Yetisen AK, Tasoglu S. Loop-mediated isothermal amplification-integrated CRISPR methods for infectious disease diagnosis at point of care. ACS Omega 2023; 8 (46) 43357-43373
- 72 Madut DB, Chemaly RF, Dadwal SS. et al. Clinical utility of plasma microbial cell-free DNA sequencing among immunocompromised patients with pneumonia. Open Forum Infect Dis 2024; 11 (08) ofae425
- 73 Hill JA, Dalai SC, Hong DK. et al. Liquid biopsy for invasive mold infections in hematopoietic cell transplant recipients with pneumonia through next-generation sequencing of microbial cell-free DNA in plasma. Clin Infect Dis 2021; 73 (11) e3876-e3883
- 74 Ranzani OT, Senussi T, Idone F. et al. Invasive and non-invasive diagnostic approaches for microbiological diagnosis of hospital-acquired pneumonia. Crit Care 2019; 23 (01) 51
- 75 Bao R, Mei Q, Yang T. et al. Comparison of endotracheal aspirate and bronchoalveolar lavage fluid metagenomic next-generation sequencing in severe pneumonia: a nested, matched case-control study. BMC Infect Dis 2023; 23 (01) 389