Bacterial Endocarditis
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TThese micrographs show a segment of mitral valve with a large vegetation. The span of the vegetation is pointed out in the H&E stained section. The segment of valve tissue is delineated by the red dotted line in the H&E and in the Movat stain. There is hemorrhage and fibrin deposition flanking the mid portion of the valve and the upper surface. This area is the “seat” of the vegetation. The white dotted line in all four stains shows an area of the fibrinous vegetation where colonies of bacteria are visible. The Gram stain for bacteria shows that the microorganisms stain in blue (Gram + cocci). The same colonies stain distinctly as black microorganisms in the GMS stain. Once you identify these in the Gram and GMS you will see that they are also visible as slightly blue colonies in both the H&E and the Movat.
