We also search for clinical criteria supposed to be linked to an infection with such a resistant strain; we check for the demographic data, conditions at admission, antibiotic treatment before or at admission, procedures considered at high risk for health-care infections such as surgery, especially in the period of great instability, also endovascular procedures, like catheter implantation or extra-corporal assistance (Extra-corporal membrane for oxygenation, Renal Replacement Therapy).