Abstract
Background: Multidrug resistant organisms (MDROs) including Methicillin resistant S. aureus (MRSA), vancomycin resistant Enterococcus (VRE) and MDR-GNB - mainly distinguished by susceptibility (MDR-GNB-CS) or resistance (MDR-GNB-CR) to carbapenems - are of global concern. There is a paucity of evidence on the prevalence of MDRO co-colonisation, which can pose a challenge to clinical management and affect patient’s outcomes. In addition, the risk factors for co-colonisation with multiple MDROs are not well defined. Methods: We performed a retrospective analysis using electronic data of 70,479 patients admitted to one of our 16 intensive care units at a university hospital in Berlin between 2018 and 2023. Only patients who had at least one nasal or rectal screening or whose clinical samples tested positive for MDROs were included in the analysis. Associations between the detection of multiple MDROs and clinical findings were assessed in multivariable analyses.Results: 47% (n=33,088) of patients admitted to our ICUs were screened for MDROs and included in our analysis. 20.5% (n=6,781) of screened patients tested positive for MDRO. A further 834 patients who were not screened had MDROs detected only in clinical specimens, giving a total of 7,705 MDRO-positive patients. 4.9% of MDRO patients were co-colonised with more than one MDRO, most commonly with VRE and MDR-CS-GNB (44% of co-colonised patients). Analysis of potential risk factors for co-colonisation showed increased likelihoods for patients with cystic fibrosis (CF, OR: 5.7), chronic kidney disease (CKN; OR: 1.3), pulmonary disease (CPD; OR: 1.5) and younger age (OR: 1.2). Conclusion: Co-colonisation occurred in almost 5 % of the screened patients in our intensive care unit. MDR-CS-GNB and VRE were most frequently detected in co-colonised patients (44%). We showed that conditions with a potentially high rate of antibiotic prescriptions such as CF or CPD were associated with a higher probability of co-colonisation but further investigations are required.