Fig. 2

Microscopic appearance of the patient in this case report. A, B Elastica-Masson staining, C hematoxylin–eosin staining, D Brown–Brenn Gram staining. A Low-power view of the aneurysm (margin between the native aorta and aneurysmal lesion). Loss of the aortic intima and media in the area of the aneurysm. Yellow asterisks showed the media of the native aorta. B Fragmented aortic media (arrows) and atheromatous plaque (asterisk) in the aneurysmal wall. C Marked infiltration of neutrophils in the aneurysmal wall. D Bacilli stained red was detected by Brown–Brenn Gram staining. E Multiple capsular PCR typing system for P. multocida isolated. The isolate only showed the expected PCR product of approximately 460 bp but negative for types A, B, D, E, and F. The PCR products were run by a 1.5% (w/v) agarose gel electrophoresis in a 1× TBE Buffer system and stained with ethidium bromide. M; marker, Lane 1: P. multocida isolated, Lane 2: PCR-negative control. F The PCR reaction assay for identifying P. multocida in the aorta of the case. Specific targets were amplified by PCR using the kmt1 gene universal primers, showing detection of the 169-bp products. The products were electrophoresed on a 3% agarose gel. M; marker, Lane 1: the positive control, Lane 2: the case, Lane 3: PCR-negative control. Scale bar = 2 mm (A), 500 µm (B), 200 µm (C), and 10 µm (D)