Risk factors for colonisation by Multidrug-Resistant bacteria in critical care units

•We identified risk factors for colonisation by specific multidrug-resistant bacteria in Intensive Care Units.•Longer Intensive Care Unit stays are linked with a higher nosocomial colonisation risk.•7541 cases analysed to identify specific colonisation patterns.•Critical need for better prevention and control strategies against antimicrobial resistance in healthcare settings. Antimicrobial resistance is a major public health challenge recognised by the WHO as an urgent global healthcare concern. Patients in Intensive Care Units (ICUs) are particularly prone to colonisation and/or infection by multidrug-resistant organisms (MDROs). Delineate the epidemiological characteristics and risk factors for MDROs colonisation in mixed ICUs and Resuscitation Units by focusing on initial and nosocomial colonisation. A descriptive observational study with analytical elements. It uses the Zero-Resistance register from the Preventive Medicine Service of the Albacete General University Hospital (Spain) from April 2016 to December 2021. It identifies the risk factors for MDROs colonisation. Of 7,541 cases, 61.0 % with initial colonisation had risk factors for MDROs versus 34.0 % not colonised upon hospitalisation (p