Legionella pneumophila

Legionella pneumophila is a Gram-negative, aerobic rod-shaped bacterium that belongs to the genus Legionella.

Legionella pneumophila causes the following diseases:

  • Legionella pneumonia (Legionnaires’ disease)

  • Pontiac fever (a non-specific infection, e.g., with fever, myalgia, and cough, but without pneumonia)

Legionella pneumophila bacteria occur primarily in freshwater and soil. Biofilms with temperatures of ≤ 63 °C, such as in pipes, cooling towers, air conditioners, and air humidifiers, are a major reservoir of infection for humans. The pathogens exhibit optimal growth at temperatures between 25 and 40°C.

Relevance of pathogen in transmission in endoscopy

  • Gastroenterology: Not relevant

  • Pulmonology: High

  • Ear, nose, and throat: High

  • Urology: Not relevant

Relevance for endoscope surveillance

  • High concern organism

Transmission route

Transmission is primarily by inhalation of aerosols containing the pathogen, e.g., from air conditioners, water pipes, and air humidifiers. There is no direct human to human transmission.

Legionella pneumophila can also be spread and transmitted in water in healthcare facilities. If the water for final rinsing during endoscope reprocessing contains Legionella, this may cause a recontamination of the endoscope. The microbiological quality of the water for final rinsing is therefore of high importance.

Resistance to antibiotics

In practice, antibiotic resistance currently plays no role. However, studies show a decreased susceptibility to various antibiotics.

Sources and further readings

  1. Gries O, Ly T: Infektologie – Kompendium humanpathogener Infektionskrankheiten und Erreger, Springer-Verlag Berlin Heidelberg, 2019.

  2. Legionella (Legionnaires’ Disease and Pontiac Fever), Centers for Disease Control and Prevention, https://www.cdc.gov/legionella/index.html. Accessed on 05.12.2021.

  3. Legionellosis, World Health Organization, https://www.who.int/news-room/fact-sheets/detail/legionellosis. Accessed on 05.12.2021.

  4. Pappa O et al. Antibiotic Resistance of Legionella pneumophila in Clinical and Water Isolates — A Systematic Review, Int. J. Environ. Res. Public Health 2020, 17, 5809.

  5. RKI-Ratgeber Legionellose, Epidemiologisches Bulletin, 5. September 2019/No. 36.