P. aeruginosa is an opportunistic bacterium known to be responsible for numerous healthcare-associated infections, particularly in intensive care units (ICU). The frequency of these infections seems to have increased during the first waves of the COVID-19 pandemic. Identifying cases of co-infection and secondary infections with P. aeruginosa in patients with COVID-19 would provide a better understanding of the epidemiological evolution and characteristics of infected patients.

Treatment of P. aeruginosa infections requires the use of antibiotics. Antibiotic resistance is a growing problem, with an increase in resistance among P. aeruginosa strains. The misuse of antibiotics to treat patients can accentuate the phenomenon of antibiotic resistance, and failure to take account of resistance revealed by antibiograms can compromise patient recovery. Analysis of bacteriological results and patient medical records would enable a posteriori evaluation of the proper use of antibiotics (choice and adaptation of molecules, doses and duration of prescriptions), and identify any areas for improvement.

The main objective is to describe the evolution of P. aeruginosa infections in ICU patients 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 identified among included patients (sampling sites and resistance profiles), to assess antibiotic prescriptions for these patients and to describe the relapse rate of included patients with a first P. aeruginosa infection.

Inclusion Criteria:

• Adult patients hospitalized for at least 48 h in an intensive care unit (ICU) at CHRU-Nancy for acute respiratory distress syndrome due to COVID-19.
• Patients hospitalized from 1st March 2020 to 31st May 2021.
• Patient developed an hospital-acquired infection caused by P. aeruginosa during their ICU stay.

Exclusion Criteria:

• Patients <18 years old.
• Patient without COVID-19 at the ICU admission.
• Patients with P. aeruginosa isolated <48 hours following ICU admission.
• Patients who did not want to be included in the study.

All patient hospitalized between 01/03/20 and 31/05/21 in an intensive care unit of the Nancy University Hospital for at less 48 h for COVID-19 acute respiratory distress syndrome and developed an hospital-acquired infection caused by P. aeruginosa during their stay in the intensive care unit.