Cefiderocol is a new antibiotic from the siderophore cephalosporin family for which there are few real-life data on its use in the treatment of infections with multidrug-resistant Gram-negative bacilli.

The circulation of bacterial strains multi-resistant to antibiotics is important at the Strasbourg University Hospital, so the investigators wish to report their local experience of the 1st uses of Cefiderocol in the treatment of infections with multi-resistant Gram-negative bacilli to antibiotics in order to better clarify the use of this antibiotic (therapeutic indication, method of administration)

Inclusion criteria:

• Adult patient (≥18 years old)
• taken care of in the HUS and treated as part of routine care with Cefiderocol between 04/01/2020 and 08/31/2022.
• Subjects who have not expressed their opposition to the reuse of their data for scientific research purposes.

Exclusion criteria:

- Patient who has expressed his opposition to the retrospective reuse of his data for scientific research purposes.

Adult patient (≥18 years old) taken care of in the HUS and treated as part of routine care with Cefiderocol between 04/01/2020 and 08/31/2022.