Interaction of B henselae with endothelial cells and erythrocytes. (A) CLSM of adherent and intracellular B henselae in endothelial cells (ECs, top row) and erythrocytes (bottom row; 100 000 cells each, respectively). Green signal indicates extracellular bacteria; blue signal, intracellular bacteria; and red signal, filamentous actin. (B) The number of intracellular bacteria was determined by gentamicin protection assays. *Significant difference compared with ECs (P < .01).