Résumé
Severe community-acquired pneumonia (CAP) is a common cause of hospitalization in ICU with a high mortality rate, and the incrimination of viruses is an ongoing topic. The aim of the study was to describe the ecology of severe CAP in our ICU, to assess the impact of molecular testing on aetiological diagnosis and to report the prevalence of coinfections. Methods: a single center retrospective study on adult patients admitted in ICU for severe CAP and matching the IDSA/ATS criteria. Available respiratory sample and Legionella urinary antigen test were compulsory. In addition to the laboratory results available, we performed a systematic respiratory panel PCR and legionella culture. The primary endpoint was the proportion of each pathogen identified in the respiratory samples. The secondary endpoints were the proportion of patients for whom respiratory panel molecular tests had an impact on diagnosis and indicated a theoretical modification of the antimicrobial therapy, the proportions of patients with coinfections and mortality.Results: a total of 104 patients were included with a median SAPS II score of 46.5 (IQR 24.5). Severe CAP were documented in 67% cases. The most frequent pathogens were influenza A/B, Streptococcus pneumoniae and rhinovirus. Systematic use of respiratory panel molecular testing benefited to the diagnosis of 28 patients (27%) with 20 cases of viral induced severe CAP and 8 cases of coinfections. It is worth noting that 2 of 6 Legionella severe CAP were only detected by the PCR, these were due to Legionella spp. Overall mortality reached 39% by the 3rd month.Conclusion: two third of the population had a positive aetiological diagnosis and the mortality was high. The three most frequent pathogens were influenza viruses, Streptococcus pneumoniae and rhinovirus.Using respiratory panel PCR tests on all samples helped to improve diagnosis and showed that viral aetiologies were frequent in this cohort of severe CAP.