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Case Reports
. 2022 Jan 28:9:819425.
doi: 10.3389/fmed.2022.819425. eCollection 2022.

Case Report: Community-Acquired Legionella gormanii Pneumonia in an Immunocompetent Patient Detected by Metagenomic Next-Generation Sequencing

Cheng Lei  1   2   3 , Xianglin Zhou  1   2   3 , Shuizi Ding  1   2   3 , Yingjie Xu  1   2   3 , Binyi Yang  1   2   3 , Wei Guo  1   2   3 , Min Song  1   2   3 , Min Yang  1   2   3 , Yunan Jia  1   2   3 , Hong Luo  1   2   3
Affiliations
Case Reports

Case Report: Community-Acquired Legionella gormanii Pneumonia in an Immunocompetent Patient Detected by Metagenomic Next-Generation Sequencing

Cheng Lei et al. Front Med (Lausanne). .

Abstract

Background: Legionella spp. has been well-recognized as an important cause of community-acquired pneumonia. Current community-acquired pneumonia guidelines recommended covering the treatment of Legionella because of the high mortality associated with inadequate antibiotic treatments. However, the symptom of Legionella pneumonia is non-specific, and routine diagnostic tests exhibit low sensitivity for Legionella spp., especially for non-Legionella pneumophila serogroup 1 strains.

Case presentation: We report a 53-year-old man without underlying diseases admitted to respiratory intensive care unit because of severe community-acquired pneumonia and respiratory failure. Although, the results of routine culture of bronchoalveolar lavage fluid and the Legionella urinary antigen test were all negative, metagenomic next-generation sequencing (mNGS) identified a great amount of DNA and RNA sequences of Legionella gormanii in bronchoalveolar lavage fluid while negative in blood sample. The presence of Legionella gormanii in bronchoalveolar lavage fluid was further confirmed by polymerase-chain-reaction and Sanger sequencing.

Conclusion: Legionella gormanii has rarely been reported in patients with community-acquired pneumonia mainly due to lack of diagnostic test for non-Legionella pneumophila serogroup 1 strains. This is the first report of Legionella gormanii pneumonia in an immunocompetent patient detected by mNGS, which indicates that mNGS is a high-resolution and sensitive assay for the diagnosis and surveillance of Legionella infection.

Keywords: Legionella gormanii; bronchoalveolar lavage fluid; community-acquired pneumonia; metagenomic next-generation sequencing (mNGS); pathogen diagnosis.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Chest computed tomography of the patient on 2 days before admission (day −2), and day 11, 22, and 42 (20 days after discharge) after admitted to our hospital. Arrows indicated the right lung developed interstitial infiltrates on day 11.
Figure 2
Figure 2
The clinical course of the patient with Legionella gormanii infection.
Figure 3
Figure 3
The bronchoalveolar lavage fluid mNGS results of the patient. (A) The DNA mNGS results showed that the coverage of Legionella gormanii was 13.52%. (B) 95.76% of the microbe DNA sequences were Legionella gormanii. (C) The RNA mNGS results showed that the coverage of Legionella gormanii was 4.24%. (D) 47.85% of the microbe RNA sequences were Legionella gormanii.
Figure 4
Figure 4
Polymerase-chain-reaction and the capillary electrophoresis technique confirmed the Legionella gormanii infection in the patient. Lane Patient: the bronchoalveolar lavage fluid sample of the patient; Lane Control 1: the blank control; Lane Control 2: the negative control, the bronchoalveolar lavage fluid sample from a patient who was finally diagnosed without Legionella pneumonia.
See this image and copyright information in PMC

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