Fig. 1.

Characterization of the rat central venous catheter biofilm infection model. (A) Correlation of daily central venous catheter blood draws and harvested catheter CFU. Rat central venous catheters were infected with Staphylococcus epidermidis ATCC 35984. At various time points, rats were sacrificed immediately following central venous catheter blood draws, and catheters were harvested and processed for the quantification of CFU/ml. Each data point (from a single animal, except where noted) represents the log₁₀ CFU/ml from a central venous catheter blood draw and the corresponding log₁₀ CFU/ml value from the harvested catheter. Central venous catheter blood draws are a good measure of the level of central venous catheter infection based on the high correlation seen in these data. (B) Harvested catheters, infected 4 days previously, were submerged in 10% formalin for 72 h before processing for routine sectioning and staining. The top photomicrograph, a hematoxylin- and eosin-stained section, shows remnant blood cells in the interior of the catheter (left side) and darkly stained bacterial cells (labeled “bc”) along the internal catheter edge. The bottom photomicrograph is a Gram-stained section showing a biofilm nearly 10 μm wide.