• Filters
  • only
  • only
  • only
  • only
  • only
  • only
  • only
  • only
  • only

Select All / Deselect All

Reset

Karius Medical Case Report: Legionella pneumophila

Legionnaires’ disease is a severe form of pneumonia caused by the gram-negative bacterium Legionella pneumophila. It has a case fatality rate of 8-12%, with risk factors including advanced age, smoking, or a suppressed immune system.

The disease presents with symptoms such as fever, chills, cough, headache, diarrhea, and delirium, but it isn’t readily distinguishable from other types of pneumonia, making diagnosis a challenge.

L. pneumophila is a bacterium commonly found in water when the temperature is between 25 and 42°C. This includes freshwater sources like hot tubs, fountains, grocery store misting devices, and water towers.

Transmission to humans generally happens via inhalation of water droplets in the air, although there are cases of direct person-to-person transmission of Legionnaires’ disease as well. L. pneumophila does not grow well on conventional culture media, so diagnosis is often through a specific Legionella urine antigen test.

Case Report: Targeted Treatment for Renal Transplant Patient

Clinical Scenario: A 58 yo renal transplant patient with subsequent rejection was admitted with nausea, vomiting, shortness of breath, and fever. He recently traveled to Asia and was on an immunosuppressive cocktail of belatacept, mycophenolate mofetil, and prednisone. A chest CT scan showed bilateral patchy infiltrates.

The patient was started on broad-spectrum antibiotics including azithromycin and meropenem as empiric coverage for atypical pneumonia.

Karius Test Result: Legionella pneumophila

The Karius test result and the Legionella urine antigen test were both positive for L. pneumophila, which gave the physician confidence to narrow therapy and target Legionella with just the azithromycin.

This is part of a series of Karius Medical Case Reports. In this case, the Karius test was able to accurately identify infection with L. pneumophila in a clinically relevant timeframe, enabling the physician to provide precise treatment to her patient. We will discuss additional case reports in future posts.

REFERENCES

  1. Wickramasekaran et. al. Legionnaires’ Disease and Associated Comorbid Conditions as Causes of Death in the U.S., 2000–2010. Public Health Reports (2015) 130(3): 222–229.
  2. Fields et. al. Legionella and Legionnaires’ Disease: 25 Years of Investigation. Clinical Microbiology Reviews (2002) 15(3): 506–526.
  3. Borges et. al. Legionella pneumophila strain associated with the first evidence of person-to-person transmission of Legionnaires’ disease: a unique mosaic genetic backbone. Nature Scientific Reports (2016) 6: Article 26261.

DISCLAIMER: CASE DESCRIPTIONS HAVE BEEN MODIFIED TO PROTECT PATIENT PRIVACY AND, WHILE EVERY ATTEMPT HAS BEEN MADE TO PROVIDE ACCURATE INFORMATION, ERRORS MAY OCCUR. THIS INFORMATION IS PROVIDED FOR EDUCATIONAL PURPOSES ONLY, AND IS NOT INTENDED TO BE USED AS MEDICAL ADVICE.

- Medical Case Report