Legionella infection - Symptoms, Causes, Images, and Treatment Options

Diseases

Highlights & Basics

Key Highlights

Legionella infection is acquired by inhalation of aerosolized bacteria or, rarely, microaspiration of contaminated drinking water.
Presentation includes respiratory symptoms such as cough (may not be productive) and shortness of breath, fever, chills, and chest pain. Other symptoms include headache, nausea, vomiting, abdominal pain, or diarrhea.
Definitive diagnosis is made with a positive laboratory test.
First-line treatment is with a fluoroquinolone or a newer-generation macrolide.
Complications are the same as those for pneumonia and include respiratory failure, parapneumonic effusion, empyema, lung abscess, and death.

Quick Reference

History & Exam
- Key Factors
- Other Factors
More information...
Diagnostics Tests
More information...
Treatment Options
More information...

Definition

Epidemiology

Etiology

Pathophysiology

Images

Chest x-ray showing infection: right lower lobe infiltrate consistent with pneumonia (arrow). confirmed positive with urinary antigen test
Chest x-ray (lateral) showing infection: posterior segment of lower lobe consistent with pneumonia; the area in the triangle is normally clear (black). confirmed with positive urinary antigen test
A portable anterior/posterior chest radiograph showing a right lower lobe infiltrate consistent with Legionnaire's disease
The superior aspect of a CT abdomen with contrast showing a right lower lobe, dense, lobar infiltrate consistent with Legionnaires' disease causing pneumonia with a small left pleural effusion

Citations

Key Articles

Phin N, Parry-Ford F, Harrison T, et al. Epidemiology and clinical management of Legionnaires' disease. Lancet Infect Dis. 2014 Oct;14(10):1011-21.[Abstract][Full Text]
Centers for Disease Control and Prevention. CDC Yellow Book 2024: health information for international travel. Section 5: travel-associated infections & diseases (bacterial) - legionnaires' disease & pontiac fever. May 2023 [internet publication].[Full Text]
US Centers for Disease Control and Prevention. Legionella (Legionnaires' disease and pontiac fever): diagnosis, treatment, & prevention. March 2021 [internet publication].[Full Text]
Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America. Am J Respir Crit Care Med. 2019 Oct 1;200(7):e45-67.[Abstract][Full Text]

Other Online Resources

CDC: Legionella (Legionnaires' disease and Pontiac fever)
Legionella.org

Referenced Articles

1. Cianciotto NP. Pathogenicity of Legionella pneumophila. Int J Med Microbiol. 2001 Nov;291(5):331-43. [Abstract]
2. Gupta SK, Imperiale TF, Sarosi GA. Evaluation of the Winthrop-University Hospital criteria to identify Legionella pneumonia. Chest. 2001 Oct;120(4):1064-71.[Abstract]
3. Lowry PW, Tompkins LS. Nosocomial legionellosis: a review of pulmonary and extrapulmonary syndromes. Am J Infect Control. 1993 Feb;21(1):21-7.[Abstract]
4. Phin N, Parry-Ford F, Harrison T, et al. Epidemiology and clinical management of Legionnaires' disease. Lancet Infect Dis. 2014 Oct;14(10):1011-21.[Abstract][Full Text]
5. Hlavsa MC, Aluko SK, Miller AD, et al. Outbreaks associated with treated recreational water - United States, 2015-2019. MMWR Morb Mortal Wkly Rep. 2021 May 21;70(20):733-38.[Abstract][Full Text]
6. US Centers for Disease Control and Prevention. Legionnaires' disease surveillance summary report, United States 2018-2019. Mar 2021 [internet publication].[Full Text][Full Text]
7. European Centre for Disease Prevention and Control (ECDC). Legionnaires' disease: annual epidemiological report for 2021. Jul 2023 [internet publication].[Full Text]
8. Allgaier J, Lagu T, Haessler S, et al. Risk factors, management, and outcomes of Legionella pneumonia in a large, Nationally Representative Sample. Chest. 2021 May;159(5):1782-92.[Abstract]
9. Beauté J, The European Legionnaires' Disease Surveillance Network. Legionnaires' disease in Europe, 2011 to 2015. Euro Surveill. 2017 Jul 6;22(27).[Abstract][Full Text]
10. Centers for Disease Control and Prevention. CDC Yellow Book 2024: health information for international travel. Section 5: travel-associated infections & diseases (bacterial) - legionnaires' disease & pontiac fever. May 2023 [internet publication].[Full Text]
11. Neil K, Berkelman R. Increasing incidence of legionellosis in the United States, 1990-2005: changing epidemiologic trends. Clin Infect Dis. 2008 Sep 1;47(5):591-9.[Abstract]
12. Soda EA, Barskey AE, Shah PP, et al. Vital signs: health care-associated Legionnaires' disease surveillance data from 20 states and a large metropolitan area - United States, 2015. MMWR Morb Mortal Wkly Rep. 2017 Jun 9;66(22):584-9.[Abstract]
13. Fields BS, Benson RF, Besser RE. Legionella and Legionnaires' disease: 25 years of investigation. Clin Microbiol Rev. 2002 Jul;15(3):506-26.[Abstract]
14. Gomez-Valero L, Rusniok C, Buchrieser C. Legionella pneumophila: population genetics, phylogeny and genomics. Infect Genet Evol. 2009 Sep;9(5):727-39. [Abstract]
15. Sabria M, Yu VL. Hospital-acquired legionellosis: solutions for a preventable infection. Lancet Infect Dis. 2002 Jun;2(6):368-73.[Abstract]
16. Payne NR, Horwitz MA. Phagocytosis of Legionella pneumophila is mediated by human monocyte complement receptors. J Exp Med. 1987 Nov 1;166(5):1377-89.[Abstract][Full Text]
17. Winn WC Jr, Myerowitz RL. The pathology of the Legionella pneumonias: A review of 74 cases and the literature. Hum Pathol. 1981 May;12(5):401-22.[Abstract]
18. Straus WL, Plouffe JF, File TM, et al. Risk factors for domestic acquisition of Legionnaires disease. Ohio Legionnaires Disease Group. Arch Intern Med. 1996 Aug 12-26;156(15):1685-92.[Abstract]
19. Den Boer JW, Nijhof J, Friesema I. Risk factors for sporadic community-acquired Legionnaires' disease. A 3-year national case-control study. Public Health. 2006 Jun;120(6):566-71.[Abstract]
20. el-Ebiary M, Sarmiento X, Torres A, et al. Prognostic factors of severe Legionella pneumonia requiring admission to ICU. Am J Respir Crit Care Med. 1997 Nov;156(5):1467-72.[Abstract][Full Text]
21. Lanternier F, Tubach F, Ravaud P, et al. Incidence and risk factors of Legionella pneumophila pneumonia during anti-tumor necrosis factor therapy: a prospective French study. Chest. 2013 Sep;144(3):990-8.[Abstract]
22. Centers for Disease Control and Prevention. Morbidity and mortality weekly report: suspected Legionella transmission from a single donor to two lung transplant recipients - Pennsylvania, May 2022. Sep 2023 [internet publication].[Full Text]
23. Stout JE, Yu V. Legionellosis. N Engl J Med. 1997 Sep 4;337(10):682-7.[Abstract]
24. Jernigan DB, Hofmann J, Cetron MS, et al. Outbreak of Legionnaires' disease among cruise ship passengers exposed to a contaminated whirlpool spa. Lancet. 1996 Feb 24;347(9000):494-9.[Abstract]
25. Miyamoto H, Jitsurong S, Shiota R, et al. Molecular determination of infection source of a sporadic Legionella pneumonia case associated with a hot spring bath. Microbiol Immunol. 1997;41(3):197-202.[Abstract]
26. Bhopal RS, Fallon RJ, Buist EC, et al. Proximity of the home to a cooling tower and risk of non-outbreak Legionnaires' disease. BMJ. 1991 Feb 16;302(6773):378-83.[Abstract]
27. Marrie TJ, Haldane D, MacDonald S, et al. Control of endemic nosocomial Legionnaires' disease by using sterile potable water for high risk patients. Epidemiol Infect. 1991 Dec;107(3):591-605.[Abstract]
28. Hlady WG, Mullen RC, Mintz CS, et al. Outbreak of Legionnaire's disease linked to a decorative fountain by molecular epidemiology. Am J Epidemiol. 1993 Oct 15;138(8):555-62.[Abstract]
29. Bangsborg JM, Uldum S, Jensen JS, et al. Nosocomial legionellosis in three heart-lung transplant patients: case reports and environmental observations. Eur J Clin Microbiol Infect Dis. 1995 Feb;14(2):99-104.[Abstract]
30. Franzin L, Scolfaro C, Cabodi D, et al. Legionella pneumophila pneumonia in a newborn after water birth: a new mode of transmissions. Clin Infect Dis. 2001 Nov 1;33(9):e103-4.[Abstract]
31. Nolt D, O'Leary ST, Aucott SW. Risks of infectious diseases in newborns exposed to alternative perinatal practices. Pediatrics. 2022 Feb 1;149(2):e2021055554.[Abstract][Full Text]
32. Currie SL, Beattie TK, Knapp CW, et al. Legionella spp. in UK composts-a potential public health issue? Clin Microbiol Infect. 2014 Apr;20(4):O224-9.[Abstract]
33. Garcia-Vidal C, Labori M, Viasus D, et al. Rainfall is a risk factor for sporadic cases of Legionella pneumophila pneumonia. PLoS One. 2013 Apr 16;8(4):e61036.[Abstract][Full Text]
34. Centers for Disease Control and Prevention. Environmental infection control guidelines. 2019 [internet publication].[Full Text]
35. Cachafeiro SP, Naveira IM, García IG. Is copper-silver ionisation safe and effective in controlling legionella? J Hosp Infect. 2007 Nov;67(3):209-16. [Abstract]
36. Mulazimoglu L, Yu VL. Can Legionnaires disease be diagnosed by clinical criteria? A critical review. Chest. 2001 Oct;120(4):1049-53.[Abstract]
37. Carratala J, Garcia-Vidal C. An update on Legionella. Cur Opin Infect Dis. 2010 Apr;23(2):152-7.[Abstract]
38. Shimada T, Noguchi Y, Jackson JL, et al. Systematic review and metaanalysis: urinary antigen tests for Legionellosis. Chest. 2009 Dec;136(6):1576-85.[Abstract]
39. Public Health England. Guidance on investigating cases, clusters and outbreaks of Legionnaires' disease. January 2021 [internet publication].[Full Text]
40. US Centers for Disease Control and Prevention. Legionella (Legionnaires' disease and pontiac fever): diagnosis, treatment, & prevention. March 2021 [internet publication].[Full Text]
41. Maze MJ, Slow S, Cumins AM, et al. Enhanced detection of Legionnaires' disease by PCR testing of induced sputum and throat swabs. Eur Respir J. 2014 Feb;43(2):644-6.[Abstract][Full Text]
42. Edelstein PH, Cianciotto NP. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 6th ed. Philadelphia, PA: Elsevier; 2005:2711-24.
43. Dominguez J, Gali N, Blanco S, et al. Assessment of a new test to detect Legionella urinary antigen for the diagnosis of Legionnaires' disease. Diagn Microbiol Infect Dis. 2001 Dec;41(4):199-203.[Abstract]
44. Dominguez J, Gali N, Matas L, et al. Evaluation of a rapid immunochromatographic assay for the detection of Legionella antigen in urine samples. Eur J Clin Microbiol Infect Dis. 1999 Dec;18(12):896-8.[Abstract]
45. Ramirez JA, Ahkee S, Tolentino A, et al. Diagnosis of Legionella pneumophila, Mycoplasma pneumoniae, or Chlamydia pneumoniae lower respiratory infection using the polymerase chain reaction on a single throat swab specimen. Diagn Microbiol Infect Dis. 1996 Jan;24(1):7-14.[Abstract]
46. Stout, JE, Rihs, JD, Yu, VL. Legionella. In: Murray PR, Baron EJ, Jorgensen JH, et al, eds. Manual of clinical microbiology. Washington, D.C.: ASM Press; 2003.
47. Plouffe JF, File TM, Breiman RF; et al. Reevaluation of the definition of Legionnaires' disease: use of the urinary antigen assay. Community Based Pneumonia Incidence Study Group. Clin Infect Dis. 1995 May;20(5):1286-91.[Abstract]
48. González-Moraleja J, Sesma P, González C, et al. [What is the cost of inappropriate admission of pneumonia patients?]. [in spa]. Arch Bronconeumol. 1999 Jul-Aug;35(7):312-6.[Abstract]
49. Fine MJ, Auble TE, Yealy DM, et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med. 1997 Jan 23;336(4):243-50.[Abstract]
50. Lim WS, van der Eerden MM, Laing R, et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 2003 May;58(5):377-82.[Abstract][Full Text]
51. España PP, Capelastegui A, Gorordo I, et al. Development and validation of a clinical prediction rule for severe community-acquired pneumonia. Am J Respir Crit Care Med. 2006 Dec 1;174(11):1249-56.[Abstract][Full Text]
52. Charles PG, Wolfe R, Whitby M, et al. SMART-COP: a tool for predicting the need for intensive respiratory or vasopressor support in community-acquired pneumonia. Clin Infect Dis. 2008 Aug 1;47(3):375-84.[Abstract][Full Text]
53. Restrepo MI, Mortensen EM, Rello J, et al. Late admission to the ICU in patients with community-acquired pneumonia is associated with higher mortality. Chest. 2010 Mar;137(3):552-7.[Abstract][Full Text]
54. Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America. Am J Respir Crit Care Med. 2019 Oct 1;200(7):e45-67.[Abstract][Full Text]
55. Brown SM, Jones JP, Aronsky D, et al. Relationships among initial hospital triage, disease progression and mortality in community-acquired pneumonia. Respirology. 2012 Nov;17(8):1207-13.[Abstract][Full Text]
56. Phua J, Ngerng WJ, Lim TK. The impact of a delay in intensive care unit admission for community-acquired pneumonia. Eur Respir J. 2010 Oct;36(4):826-33.[Abstract][Full Text]
57. Aliberti S, Ramirez J, Cosentini R, et al. Low CURB-65 is of limited value in deciding discharge of patients with community-acquired pneumonia. Respir Med. 2011 Nov;105(11):1732-8.[Abstract][Full Text]
58. Sharp AL, Jones JP, Wu I, et al. CURB-65 performance among admitted and discharged emergency department patients with community-acquired pneumonia. Acad Emerg Med. 2016 Apr;23(4):400-5.[Abstract][Full Text]
59. Chahin A, Opal SM. Severe pneumonia caused by Legionella pneumophila: differential diagnosis and therapeutic considerations. Infect Dis Clin North Am. 2017 Mar;31(1):111-21.[Abstract][Full Text]
60. Benin AL, Benson RF, Besser RE. Trends in Legionnaires disease, 1980-1998: declining mortality and new patterns of diagnosis. Clin Infect Dis. 2002 Nov 1;35(9):1039-46.[Abstract]
61. Heath CH, Grove DI, Looke DFM. Delay in appropriate therapy of Legionella pneumonia associated with increased mortality. Eur J Clin Microbiol Infect Dis. 1996 Apr;15(4):286-90.[Abstract]
62. Arnold F, Summersgill JT, Lajoie AS, et al. A worldwide perspective of atypical pathogens in community-acquired pneumonia. Am J Respir Crit Care Med. 2007 May 15;175(10):1086-93.[Abstract]
63. Mills GD, Oehley MR, Arrol B. Effectiveness of beta lactam antibiotics compared with antibiotics active against atypical pathogens in non-severe community acquired pneumonia: meta-analysis. BMJ. 2005 Feb 26;330(7489):456.[Abstract][Full Text]
64. Shefet D, Robenshtok E, Paul M, et al. Empirical atypical coverage for inpatients with community-acquired pneumonia: systematic review of randomized controlled trials. Arch Intern Med. 2005 Sep 26;165(17):1992-2000.[Abstract][Full Text]
65. British Thoracic Society. 2015 - annotated BTS guideline for the mangement of CAP in adults (2009) summary of recommendations. Jan 2015 [internet publication].[Full Text]
66. National Institute for Health and Care Excellence. Pneumonia (community-acquired): antimicrobial prescribing. Sep 2019 [internet publication].[Full Text]
67. Mykietiuk A, Carratala J, Fernandez-Sabe N, et al. Clinical outcomes for hospitalized patients with Legionella pneumonia in the antigenuria era: the influence of levofloxacin therapy. Clin Infect Dis. 2005 Mar 15;40(6):794-9.[Abstract]
68. Edelstein PH, Shinzato T, Doyle E, et al. In vitro activity of gemifloxacin (SB-265805, LB20304a) against Legionella pneumophila and its pharmacokinetics in guinea pigs with L. pneumophila pneumonia. Antimicrob Agents Chemother. 2001 Aug;45(8):2204-9.[Abstract][Full Text]
69. Blazquez-Garrido RM, Espinosa-Parra FJ, Alemany-Frances L, et al. Antimicrobial chemotherapy for Legionnaires disease: levofloxacin versus macrolides. Clin Infect Dis. 2005 Mar 15;40(6):800-6.[Abstract]
70. Sabria M, Pedro-Botet ML, Gomez J, et al. Fluoroquinolones vs macrolides in the treatment of Legionnaires disease. Chest. 2005 Sep;128(3):1401-5.[Abstract]
71. Griffin AT, Peyrani P, Wiemken T, et al. Macrolides versus quinolones in Legionella pneumonia: results from the Community-Acquired Pneumonia Organization international study. Int J Tuberc Lung Dis. 2010 Apr;14(4):495-9.[Abstract]
72. Rusu A, Munteanu AC, Arbănași EM, et al. Overview of side-effects of antibacterial fluoroquinolones: new drugs versus old drugs, a step forward in the safety profile? Pharmaceutics. 2023 Mar 1;15(3):804.[Abstract][Full Text]
73. Dournon E, Mayaud CH, Wolff M, et al. Comparison of the activity of three antibiotic regimens in severe LD. J. Antimicrob Chemother. 1990 Oct;(suppl B):129-39.[Abstract]
74. Roig J, Rello J. Legionnaires' disease: a rational approach to therapy. J Antimicrob Chemother. 2003 May;51(5):1119-29.[Abstract][Full Text]
75. Grau S, Antonio JM, Ribes E, et al. Impact of rifampicin addition to clarithromycin in Legionella pneumophila pneumonia. Int J Antimicrob Agents. 2006 Sep;28(3):249-52. [Abstract]
76. Mallegol J, Fernandes P, Melano RG, et al. Antimicrobial activity of solithromycin against clinical isolates of Legionella pneumophila serogroup 1. Antimicrob Agents Chemother. 2014;58:909-15.[Abstract]
77. Dillon C, Guarascio AJ, Covvey JR. Lefamulin: a promising new pleuromutilin antibiotic in the pipeline. Expert Rev Anti Infect Ther. 2019 Jan;17(1):5-15.[Abstract]
78. Alexander E, Goldberg L, Das AF, et al. Oral lefamulin vs moxifloxacin for early clinical response among adults with community-acquired bacterial pneumonia: The LEAP 2 randomized clinical trial. JAMA. 2019 Nov 5;322(17):1661-71.[Abstract][Full Text]
79. National Institute for Health and Care Excellence. Pneumonia in adults: diagnosis and management. Oct 2023 [internet publication]. [Full Text]
80. El Moussaoui R, Opmeer BC, de Borgie CA, et al. Long-term symptom recovery and health-related quality of life in patients with mild-to-moderate-severe community-acquired pneumonia. Chest. 2006 Oct;130(4):1165-72.[Abstract]
81. Lettinga KD, Verbon A, Nieuwkerk PT, et al. Health-related quality of life and posttraumatic. stress disorder among survivors of an outbreak of Legionnaires disease. Clin Infect Dis. 2002 Jul 1;35(1):11-7.[Abstract][Full Text]
82. Dominguez A, Alvarez J, Sabria M, et al. Factors influencing the case-fatality rate of Legionnaires' disease. Int J Tuberc Lung Dis. 2009 Mar;13(3):407-12.[Abstract]
83. Garcia-Vidal C, Carratala J. Current clinical management of Legionnaires' disease. Expert Rev Anti Infect Ther. 2006 Dec;4(6):995-1004.[Abstract]
84. Centers for Disease Control and Prevention. Guidelines for prevention of nosocomial pneumonia. MMWR Recomm Rep. 1997 Jan 3;46(RR-1):1-79.[Abstract][Full Text]
85. European Centre for Disease Prevention and Control. European Legionnaires' Disease Surveillance Network (ELDSNet): operating procedures. January 2012 [internet publication].[Full Text]