Figure 4. Scanning electron microscopy of Nocardia spp. biofilm on silicone central venous catheters. A) N. nova complex (disseminated Nocardia bacteremia) on the surface, showing heavy biofilm matrix covering filamentous cells. B) N. nova complex (definite central line–associated bloodstream infection) showing network of filamentous (thin arrow), partially covered with opaque biofilm matrix (thick arrows). Original magnifications ×2,500.