The attached skin showed focal superficial ulceration of the overlying stratified squamous epithelium with associated prominent dermal fibrosis and chronic inflammatory cell infiltrate (IMAGE 01). A gram stain of the superficial wound (IMAGE 02) demonstrated a pleomorphic population of microorganisms including multiple thin gram negative bacilli, gram positive cocci and gram positive bacilli in chains contained within a background of polymorphonuclear cells. The underlying bony tissue showed necrotic fragments of bone surrounded by prominent fibrosis and an acute inflammatory cell infiltrate containing islands of ill-defined basophilic staining material (IMAGES 03, 04, 05). A tissue gram stain highlighted the presence of multiple organisms including thin gram negative rods (IMAGES 06, 07, 08, and 09) and large clusters of gram positive cocci.
Aerobic bacterial cultures grew group C ß-hemolytic Streptococci from both the fistula tract and deep bony tissue. Anaerobic bacterial cultures from both sites cultured showed heavy growth of Provetella melaningenicus, Bacteroides caccae, Peptostreptococcus species and Propionibacterium species. Cultures for fungal and Mycobacterial organisms were negative.