The population of these monocentric and retrospective study includes patients hospitalized in one of the critical care services of Nîmes' community hospital.

The objective is to determine the key factors that lead to satisfactory beta-lactams serum concentrations in critically ill patients.

Clinical and biological features, as well as risk scores are collected and recorded into an electronic Case Report Form.

The primary outcome is to show the main characteristics related to adequate beta-lactams serum concentrations in critically ill inpatients.

Secondary outcomes include the key factors related to inadequate beta-lactams serum concentrations in critically ill inpatients, Therapeutic Drug Monitoring (TDM) impact in the achievement of target beta-lactams serum concentration and the correlation between Aminoglycosides and Beta-lactams serum concentrations. Do both antibiotics have similar elimination kinetics ?

Inclusion Criteria:

• Patient aged at least (≥) 18 years of age.
• Patient (or his representative for patients unable to give their consent) has given his free and informed consent and has signed the consent form.
• Patient affiliated to the health insurance scheme
• Patient hospitalized in one of the critical care services of Nimes' community hospital with at least one beta-lactam treatment
• Patient with at least one beta-lactam TDM during his stay

Exclusion Criteria :

• Patient who did not consent the use of his personal data
• Patients under maintenance of justice, tutelage or legal guardianship
• Patient previously included in the study.

Adult patients admitted to a critical care unit and treated for an infectious episode with beta-lactam, who received a Therapeutic Drug Monitoring. All patients older than 18 years recorded between 1/1st/2018 and 3/4th/2021 were included.