FIGURE 1: B. cenocepacia requires macrophages for efficient replication and the induction of acute pro-inflammatory disease. Zebrafish larvae are highly sensitive to infection with B. cenocepacia K56-2. Injection of a small inoculum (5-50 colony forming units) causes rapid pro-inflammatory fatal disease that requires the presence of macrophages, but not neutrophils. Macrophages are important for the observed increase in il1b expression. In the absence of macrophages, either using a Pu.1 morpholino knockdown approach or chemical ablation based on the Metronidazole/Nitroreductase system, B. cenocepacia K56-2 is unable to proliferate as in wildtype. This phenomenon was observed when the bacteria were injected intravenously and subcutaneously.