A fatal case of Legionella micdadei prosthetic valve endocarditis diagnosed by plasma microbial cell-free DNA metagenomic sequencing.
M Florencia Martins, Ramesh Govindan, Nouf K Almaghlouth et al.
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Case in brief
An immunocompromised patient developed an indolent outpatient illness that progressed rapidly to mixed shock. Evaluation revealed prosthetic valve endocarditis complicated by valve dehiscence and sepsis. Plasma microbial cell-free DNA metagenomic next-generation sequencing identified Legionella micdadei, and buffered charcoal yeast extract culture of valve tissue confirmed the diagnosis. The patient died.
What made this case unusual
Legionella micdadei prosthetic valve endocarditis was diagnosed using plasma microbial cell-free DNA sequencing and confirmed by specialized culture of valve tissue, in a case that deteriorated rapidly after an indolent course.
Diagnostic / clinical pearl
In culture-negative endocarditis, plasma microbial cell-free DNA sequencing may help identify a pathogen when conventional diagnostic methods are limited; tissue culture can provide confirmation.
Why it matters
The report highlights a gap in current culture-negative endocarditis guidelines: they do not address timely diagnosis for patients at risk of rapid deterioration.