29.3% of bacteremias in intensive care units (ICU) are linked to vascular devices, including 7.7% to arterial catheters, with an influence on both morbility and mortality.

It is now accepted that biofilm as a role on bacterial development on inner surface of vascular devices but there is yet a lack of clinical relevant data documenting a causal relation between biofilm formation and bacteremias.

The investigators assume that a better structural and microbiological characterization of arterial catheter biofilm in ICU patients could help preventing bacteremias or have a more specific treatment when it appears.

Inclusion Criteria:

• Patient or relative informed of the study and having declared their non-objection
• Patient over 18 years old
• Patient hospitalized in ICU with an arterial catheter

Exclusion Criteria:

• Patient unable to express consent
• Patient whose collection of the arterial catheter is impossible or for whom storage at 4°C is impossible
• Patient with arterial catheter removed outside the usual procedure of the ICU
• Patient admitted in ICU with an arterial catheter already in place

Patient over 18 years of age with artherial catheter more than 2 calendar days