Skip to main navigation menu Skip to main content Skip to site footer

Original article

Vol. 152 No. 1718 (2022)

Legionnaires' disease – a qualitative study on Swiss physicians' approaches to the diagnosis and treatment of community-acquired pneumonia

  • Fabienne B. Fischer
  • Michael J. Deml
  • Daniel Mäusezahl
Cite this as:
Swiss Med Wkly. 2022;152:w30157


BACKGROUND: The number of reported cases of Legionnaires' disease has increased significantly over the last decade in Switzerland and abroad. Along with the number of cases, the volume of testing has increased as well, which has been partially attributed to a change in awareness of the disease. Yet, while there are numerous guidelines and recommendations for the case management of community-acquired pneumonia, little is known about how physicians in Switzerland perceive and manage Legionnaires' disease.

METHODS: This study aimed to investigate physicians' awareness of Legionnaires' disease, their information resources and their approach to the diagnosis and treatment of pneumonia (and thus Legionnaires' disease). Using a semi-structured interview guide, we conducted in-depth interviews with physicians from different levels of care and from the German-, French- and Italian-speaking regions of Switzerland.

RESULTS: We conducted 46 interviews with physicians from university, cantonal and regional hospitals as well as with general practitioners (GPs) from all three language regions. Overall, the physicians working in hospitals indicated a similar level of awareness of Legionnaires' disease, and comparable diagnosis and treatment approaches. The Legionella urine antigen test (UAT) was reported to be routinely performed in inpatients. In contrast, GPs indicated lower levels of awareness, reflecting the fact that they treat pneumonia cases empirically without identification of the causative agent, in accordance with current guidelines. The value of the diagnostic tests in general and the Legionella UAT in particular was considered to be dependent on the (preferred) antibiotic treatment approach. Some physicians saw the test as redundant, as its result would not influence treatment. This was tied to concerns about the UAT’s sensitivity and its limited use for the detection of Legionella pneumophila serogroup 1. Lastly, extrinsic constraints, such as financial and time considerations also affected physicians' testing and treatment preferences.

CONCLUSION: Awareness of Legionnaires' disease is overall high, yet cases are mainly diagnosed and reported by hospitals. Improved diagnostic tools are needed to support physicians in reducing underestimation of Legionnaires' disease and optimise antibiotic stewardship without compromising patient health outcomes.


  1. Communicable Diseases Legislation – Epidemics Act, (EpidA), (2016).
  2. Bulletin BAG. Week 1+2/2021: Federal Office of Public Health; 2021.
  3. Fastl C, Devleesschauwer B, van Cauteren D, Lajot A, Leroy M, Laisnez V, et al. The burden of legionnaires’ disease in Belgium, 2013 to 2017. Arch Public Health. 2020 Oct;78(1):92.
  4. Cassell K, Gacek P, Rabatsky-Ehr T, Petit S, Cartter M, Weinberger DM. Estimating the true burden of Legionnaires’ disease. Am J Epidemiol. 2019 Sep;188(9):1686–94.
  5. Legionnaires’ disease. Annual epidemiological report for 2019. Stockholm: ECDC: European Centre for Disease Prevention and Control, 2021.
  6. Beauté J, Robesyn E, de Jong B ; European Legionnaires’ Disease Surveillance Network. Legionnaires’ disease in Europe: all quiet on the eastern front? Eur Respir J. 2013 Dec;42(6):1454–8.
  7. Fischer FB, Schmutz C, Gaia V, Mäusezahl D. Legionnaires’ disease on the rise in Switzerland: A denominator-based analysis of national diagnostic data, 2007–2016. Int J Environ Res Public Health. 2020;17(19):7343. PubMed PMID: doi:
  8. Gysin N. Legionnaires' disease in Switzerland: analysis of Swiss surveillance data, 2000 to 2016 - spatial and seasonal determinants [MPH thesis]; 2018.
  9. Laifer G, Flückiger U, Scheidegger C. Management of community acquired pneumonia (CAP) in adults (ERS/ESCMID guidelines adapted for Switzerland). Swiss Society for Infectious Diseases; 2006.
  10. Woodhead M, Blasi F, Ewig S, Huchon G, Ieven M, Ortqvist A, et al.; European Respiratory Society; European Society of Clinical Microbiology and Infectious Diseases. Guidelines for the management of adult lower respiratory tract infections. Eur Respir J. 2005 Dec;26(6):1138–80.
  11. Legionellen und Legionellose BAG-/BLV-Empfehlungen. Federal Office of Public Health; Federal Food Safety and Veterinary Office, 2018.
  12. Höffken G, Lorenz J, Kern W, Welte T, Bauer T, Dalhoff K, et al.; Paul-Ehrlich-Society of Chemotherapy; German Respiratory Diseases Society; German Infectious Diseases Society; Competence Network CAPNETZ for the Management of Lower Respiratory Tract Infections and Community-acquired Pneumonia. Guidelines of the Paul-Ehrlich-Society of Chemotherapy, the German Respiratory Diseases Society, the German Infectious Diseases Society and of the Competence Network CAPNETZ for the Management of Lower Respiratory Tract Infections and Community-acquired Pneumonia. Pneumologie. 2010 Mar;64(3):149–54.
  13. Ewig S, Höffken G, Kern WV, Rohde G, Flick H, Krause R, et al. Behandlung von erwachsenen Patienten mit ambulant erworbener Pneumonie und Prävention - Update 2016. Pneumologie. 2016 Mar;70(3):151–200.
  14. Ewig S, Kolditz M, Pletz M, Altiner A, Albrich W, Drömann D, et al. Behandlung von erwachsenen Patienten mit ambulant erworbener Pneumonie – Update 2021. Pneumologie. 2021 Sep;75(9):665–729.
  15. Albrich W, Boillat-Blance N, Kahlert C, Hauser C, Ott S, Pedrazzini B. Pneumonie / Ambulant-erworbene Pneumonie CAP (D). 2021 [cited 2022 Feb 7]. Available from:
  16. Miyashita N, Horita N, Higa F, Aoki Y, Kikuchi T, Seki M, et al. Validation of a diagnostic score model for the prediction of Legionella pneumophila pneumonia. J Infect Chemother. 2019 Jun;25(6):407–12.
  17. Bolliger R, Neeser O, Merker M, Vukajlovic T, Felder L, Fiumefreddo R, et al. Validation of a prediction rule for Legionella pneumonia in emergency department patients. Open Forum Infect Dis. 2019 Jun;6(7):ofz268.
  18. Ito A, Ishida T, Washio Y, Yamazaki A, Tachibana H. Legionella pneumonia due to non-Legionella pneumophila serogroup 1: usefulness of the six-point scoring system. BMC Pulm Med. 2017;17(1):211-. doi: PubMed PMID: 29246145.
  19. Cunha BA. Severe Legionella pneumonia: rapid presumptive clinical diagnosis with Winthrop-University Hospital’s weighted point score system (modified). Heart Lung. 2008 Jul-Aug;37(4):311–20.
  20. Fiumefreddo R, Zaborsky R, Haeuptle J, Christ-Crain M, Trampuz A, Steffen I, et al. Clinical predictors for Legionella in patients presenting with community-acquired pneumonia to the emergency department. BMC Pulm Med. 2009 Jan;9(1):4.
  21. Phin N, Parry-Ford F, Harrison T, Stagg HR, Zhang N, Kumar K, et al. Epidemiology and clinical management of Legionnaires’ disease. Lancet Infect Dis. 2014 Oct;14(10):1011–21.
  22. Velazco JF. Legionnaires’ disease treatment. In: Surani S, editor. Hospital acquired infection and Legionnaires' disease: IntechOpen; 2020.
  23. Gale NK, Heath G, Cameron E, Rashid S, Redwood S. Using the framework method for the analysis of qualitative data in multi-disciplinary health research. BMC Med Res Methodol. 2013;13(1):117. doi: PubMed PMID: 24047204; PubMed Central PMCID: PMCPMC3848812.
  24. Tong A, Sainsbury P, Craig J. Consolidated criteria for reporting qualitative research (COREQ): a 32-item checklist for interviews and focus groups. Int J Qual Health Care. 2007 Dec;19(6):349–57.
  25. Braun V, Clarke V. Using thematic analysis in psychology. Qual Res Psychol. 2006;3(2):77–101.
  26. Sentinella: Themen 2019. Federal Office of Public Health; 2019.
  27. Federal Office of Public Health. Meldepflichtige übertragbare Krankheiten und Erreger: Leitfaden zur Meldepflicht. 2020.
  28. Carugati M, Aliberti S, Reyes LF, Franco Sadud R, Irfan M, Prat C, et al. Microbiological testing of adults hospitalised with community-acquired pneumonia: an international study. ERJ Open Res. 2018 Oct;4(4):00096–02018.
  29. Shoar S, Musher DM. Etiology of community-acquired pneumonia in adults: a systematic review. Pneumonia. 2020 Oct;12(1):11.
  30. Lim WS, van der Eerden MM, Laing R, Boersma WG, Karalus N, Town GI, et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 2003 May;58(5):377–82.
  31. Widmer CC, Bachli EB. Quality of care in patients with community acquired pneumonia and sepsis in a Swiss hospital. Swiss Med Wkly. 2012 Feb;142(0506):w13510.
  32. Shimada T, Noguchi Y, Jackson JL, Miyashita J, Hayashino Y, Kamiya T, et al. Systematic review and metaanalysis: urinary antigen tests for Legionellosis. Chest. 2009 Dec;136(6):1576–85.
  33. Muyldermans A, Descheemaeker P, Boel A, Desmet S, Van Gasse N, Reynders M ; National Expert Committee on Infectious Serology. What is the risk of missing legionellosis relying on urinary antigen testing solely? A retrospective Belgian multicenter study. Eur J Clin Microbiol Infect Dis. 2020 Apr;39(4):729–34.
  34. Rojas E, Naqvi S, Balakrishnan B. 985: Urine antigen testing for Legionnaires’ disease: Use it to rule in, not rule out! Crit Care Med. 2021;49(1):490.
  35. Piso RJ, Arnold C, Bassetti S. Coverage of atypical pathogens for hospitalised patients with community-acquired pneumonia is not guided by clinical parameters. Swiss Med Wkly. 2013 Sep;143(3738):w13870.
  36. Garbino J, Bornand JE, Uçkay I, Fonseca S, Sax H. Impact of positive legionella urinary antigen test on patient management and improvement of antibiotic use. J Clin Pathol. 2004;57(12):1302-5. doi: PubMed PMID: PMC1770495.
  37. Garin N, Marti C. Community-acquired pneumonia: the elusive quest for the best treatment strategy. J Thorac Dis. 2016 Jul;8(7):E571–4.
  38. Falcone M, Russo A, Tiseo G, Cesaretti M, Guarracino F, Menichetti F. Predictors of intensive care unit admission in patients with Legionella pneumonia: role of the time to appropriate antibiotic therapy. Infection. 2021 Apr;49(2):321–5.
  39. Ott SR, Hauptmeier BM, Ernen C, Lepper PM, Nüesch E, Pletz MW, et al. Treatment failure in pneumonia: impact of antibiotic treatment and cost analysis. Eur Respir J. 2012 Mar;39(3):611–8.
  40. Van Berge Henegouwen JM, Groeneveld GH, de Boer MG, Visser LG. A more restrictive use of quinolones in patients with community acquired pneumonia is urgently needed. Neth J Med. 2017 Dec;75(10):462–3.
  41. Schweitzer VA, van Heijl I, Boersma WG, Rozemeijer W, Verduin K, Grootenboers MJ, et al.; CAP-PACT Study Group. Narrow-spectrum antibiotics for community-acquired pneumonia in Dutch adults (CAP-PACT): a cross-sectional, stepped-wedge, cluster-randomised, non-inferiority, antimicrobial stewardship intervention trial. Lancet Infect Dis. 2022 Feb;22(2):274–83.
  42. Teixeira Rodrigues A, Roque F, Falcão A, Figueiras A, Herdeiro MT. Understanding physician antibiotic prescribing behaviour: a systematic review of qualitative studies. Int J Antimicrob Agents. 2013 Mar;41(3):203–12.
  43. Spoorenberg SM, Bos WJ, Heijligenberg R, Voorn PG, Grutters JC, Rijkers GT, et al. Microbial aetiology, outcomes, and costs of hospitalisation for community-acquired pneumonia; an observational analysis. BMC Infect Dis. 2014 Jun;14(1):335.
  44. Vestjens SM, Wittermans E, Spoorenberg SM, Grutters JC, van Ruitenbeek CA, Voorn GP, et al. Inter-hospital variation in the utilization of diagnostics and their proportionality in the management of adult community-acquired pneumonia. Pneumonia. 2018 Dec;10(1):15.
  45. Wiersinga WJ, Bonten MJ, Boersma WG, Jonkers RE, Aleva RM, Kullberg BJ, et al.; Dutch Working Party on Antibiotic Policy; Dutch Association of Chest Physicians. SWAB/NVALT (Dutch Working Party on Antibiotic Policy and Dutch Association of Chest Physicians) guidelines on the management of community-acquired pneumonia in adults. Neth J Med. 2012 Mar;70(2):90–101.
  46. Wiersinga WJ, Bonten MJ, Boersma WG, Jonkers RE, Aleva RM, Kullberg BJ, et al. Management of community-acquired pneumonia in adults: 2016 guideline update from the Dutch Working Party on Antibiotic Policy (SWAB) and Dutch Association of Chest Physicians (NVALT). Neth J Med. 2018 Jan;76(1):4–13.
  47. von Baum H, Ewig S, Marre R, Suttorp N, Gonschior S, Welte T, et al.; Competence Network for Community Acquired Pneumonia Study Group. Community-acquired Legionella pneumonia: new insights from the German competence network for community acquired pneumonia. Clin Infect Dis. 2008 May;46(9):1356–64.
  48. Blázquez RM, Espinosa FJ, Martínez-Toldos CM, Alemany L, García-Orenes MC, Segovia M. Sensitivity of urinary antigen test in relation to clinical severity in a large outbreak of Legionella pneumonia in Spain. Eur J Clin Microbiol Infect Dis. 2005 Jul;24(7):488–91.
  49. Priest PC, Slow S, Chambers ST, Cameron CM, Balm MN, Beale MW, et al. The burden of Legionnaires’ disease in New Zealand (LegiNZ): a national surveillance study. Lancet Infect Dis. 2019 Jul;19(7):770–7.
  50. Woodhead M, Blasi F, Ewig S, Garau J, Huchon G, Ieven M, et al.; Joint Taskforce of the European Respiratory Society and European Society for Clinical Microbiology and Infectious Diseases. Guidelines for the management of adult lower respiratory tract infections—full version. Clin Microbiol Infect. 2011 Nov;17 Suppl 6:E1–59.

Most read articles by the same author(s)