PMC4712205_01
PMC4712205_02
Histology of the aortic valve. (A) High power magnification of the hematoxylin-eosin stained section showed basophilic material within degenerated macrophages in a fibrinous background (original magnification 600x). (B) Small coccobacillary forms, mostly following the contours of macrophages consistent with intracellular localization and highly suggestive of bacterial organisms, were observed in the Gomori methenamine silver stain (original magnification 600x).
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PMC4712205_02_gr1.jpg
fig0005
A Gomori's methenamine silver stain demonstrated intracellular and extracellular small coccobacillary organisms (Fig. 1), but no microorganisms were apparent on the Gram and Periodic acid-Schiff stain. 16S rDNA sequencing of the valves came back positive for C. burnetii on post-operative day 10.