Pathogens isolated.

a) when polymyxins (1,145 hospitalizations) or b) tigecycline (3,125 hospitalizations) were used. Only Acinetobacter spp., E. coli, Klebsiella spp. and P. aeruginosa* are included MDR: multi-drug resistance (non-susceptibility to > = 3 drug classes) CR: carbapenem resistance (non-susceptibility to carbapenems; ertapenem not considered for non-fermenters) XDR: non-susceptibility to all tested classes except to polymyxins (definitions of MDR, CR and XDR adapted from reference [22]) *In 206/225 cases where tigecycline was given and a Pseudomonas was isolated, the patient had at least one anti-pseudomonal spectrum agent (definition of anti-pseudomonal activity based on reference [22]).