Following injection of BMDMs pretreated with PcrV for 24 h into the tissues surrounding biofilm catheters in vivo, the percentage of F4/80+iNOS+ macrophages was higher in PcrV/BMDMs treated mice than that in mice treated with non-activated BMDMs (Figure 5C), suggesting that functional M1 macrophages were present at the site of infection. This evidence concerns the gene NOS2 and infection.