P. aeruginosa is an opportunistic bacterium known to be responsible for numeroushealthcare-associated infections, particularly in intensive care units (ICU). Thefrequency of these infections seems to have increased during the first waves of theCOVID-19 pandemic. Identifying cases of co-infection and secondary infections with P.aeruginosa in patients with COVID-19 would provide a better understanding of theepidemiological evolution and characteristics of infected patients.Treatment of P. aeruginosa infections requires the use of antibiotics. Antibioticresistance is a growing problem, with an increase in resistance among P. aeruginosastrains. The misuse of antibiotics to treat patients can accentuate the phenomenon ofantibiotic resistance, and failure to take account of resistance revealed by antibiogramscan compromise patient recovery. Analysis of bacteriological results and patient medicalrecords would enable a posteriori evaluation of the proper use of antibiotics (choice andadaptation of molecules, doses and duration of prescriptions), and identify any areas forimprovement.The main objective is to describe the evolution of P. aeruginosa infections in ICUpatients with COVID-19 during the first 3 waves of COVID-19 (01/03/2020 to 31/05/2021).Secondary objectives are to describe the typology of P. aeruginosa strains identifiedamong included patients (sampling sites and resistance profiles), to assess antibioticprescriptions for these patients and to describe the relapse rate of included patientswith a first P. aeruginosa infection.