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Case Reports
. 2015 Feb;17(1):89-93.
doi: 10.1111/tid.12334. Epub 2015 Jan 9.

Mistaken identity: Legionella micdadei appearing as acid-fast bacilli on lung biopsy of a hematopoietic stem cell transplant patient

P R Waldron  1 , B A Martin, D Y Ho
Affiliations
Case Reports

Mistaken identity: Legionella micdadei appearing as acid-fast bacilli on lung biopsy of a hematopoietic stem cell transplant patient

P R Waldron et al. Transpl Infect Dis. 2015 Feb.

Abstract

Legionella micdadei is a potential cause of invasive lung infections in immunocompromised hosts. On biopsy specimens, it can appear as an acid-fast bacillus (AFB) and can be mistaken for a member of genus Mycobacterium. As Legionella requires selective media to grow in culture, and the commonly used, commercially available urine antigen test for Legionella only detects Legionella pneumophila serogroup-1, but not L. micdadei, it is important to consider this organism in the differential diagnosis for AFB in immunocompromised hosts. We report a case of L. micdadei infection, which was initially treated empirically for non-tuberculous mycobacteria based on AFB staining of biopsy tissue before the final diagnosis was made.

Keywords: Legionella micdadei; hematopoietic stem cell transplant; legionellosis; pneumonia.

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Figures

Figure 1
Figure 1
CT Thorax demonstrating a peripheral left base consolidation with air bronchogram.
Figure 2
Figure 2
CT-guided fine needle aspiration biopsy of the left lung lesion showing necrotizing inflammation with acid fast organisms (Kinyoun (AFB) stain).
Figure 3
Figure 3
BYCE plate showing colonies of L. micadadei from the patient’s lung biopsy specimen.
See this image and copyright information in PMC

References

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