Trends in the proportion of resistant bacteria involved in ventilator-associated pneumonia as the first hospital-acquired infection in intensive care units between 2003 and 2016 in Lyon, France

•Ventilator-associated pneumonia (VAP) in adults intensive care units ICUs.•Restricted risk factors for multidrug-resistant microorganisms (MDROs) infection.•Decrease of the percentage of MDROs involved in VAP over year.•23.9% of MDROs involved in VAP starting 2 days after ICU admission.•Increase of the percentage of MDROs involved in VAP after 10 days in ICUs. The aim of this study was to describe the proportion of multidrug-resistant microorganisms (MDROs) involved in ventilator-associated pneumonia (VAP) as the first hospital-acquired infection in 536 adults with restricted risk factors for MDRO-related infection. We found a significant decrease in the percentage of MDROs involved in VAP between 2003 and 2016 and this percentage increased when VAP occurred after day 10.