Exploring infection risk factors and multi-drug-resistant organisms (MDROs) in burn intensive care units: a multi-centre case-control study

Abstract

Background: Despite the widespread incidence of multi-drug-resistant organisms (MDROs) within burn centres, there is a lack of research investigating the risk of infection with MDROs in critically ill burn patients. This study aimed to identify the risk factors associated with the acquisition of MDROs among critically ill burn patients admitted to burn intensive care units (BICUs), and to determine the prevalence of MDROs in this population.

Methods: This multi-centre observational case-control study included adult patients (age ≥18 years) admitted to BICUs between January 2015 and December 2022. Patients were excluded if the burn injury affected <10% of the body surface area, they died within 24 h of ICU admission, the timing of the burn injury was unknown, and they had a history of MDRO infection within 1 year prior to admission or antibiotic use 3 months prior to admission. Risk factors for acquiring MDROs, prevalence of MDROs, ICU length of stay (LOS), hospital LOS, 30-day mortality and in-hospital mortality rates were identified as the study outcomes. An exact matching approach with a 1:1 ratio was used to match the two groups based on age, gender and admission year. Stepwise forward selection logistic and linear regression analyses were used when appropriate.

Results: In total, 173 patients were included, of which 168 patients were matched: 84 patients in the case group (MDRO group) and 84 patients in the control group (non-MDRO group). Patients in the MDRO group had lower Glasgow Coma Scale (GCS) baseline scores [unadjusted odds ratio (OR) 0.88, 95% confidence interval (CI) 0.827-0.944], higher baseline Sequential Organ Failure Assessment (SOFA) scores (unadjusted OR 1.19, 95% CI 1.069-1.329), higher APACHE II scores (unadjusted OR 1.11, 95% CI 1.054-1.161), invasive mechanical ventilation (MV) status at admission (unadjusted OR 3.76, 95% CI 1.96-7.20), and a greater proportion of total body surface area (TBSA) affected (unadjusted OR 1.04, 95% CI 1.024-1.058]) compared with the non-MDRO group. However, regression analysis showed that those with lower baseline GCS scores [adjusted OR (aOR) 0.904, 95% CI 0.828-0.987], a greater proportion of TBSA affected (aOR 1.023, 95% CI 1.002-1.045), and urinary tract infections (aOR 7.198, 95% CI 1.973-26.259) were significantly more prone to MDRO infections. The most common isolated pathogen in the MDRO group was Acinetobacter baumannii (57%), and the most common infection was pneumonia (52.4%). The duration of MV and ICU LOS were significantly longer in the MDRO group compared with the non-MDRO group. No significant differences in the other outcomes were observed between the groups.

Conclusion: This study showed a significantly increased risk of MDRO infection in patients who had burns affecting a greater proportion of TBSA, lower GCS scores, and higher SOFA and APACHE II scores. Future studies with larger sample sizes are needed to confirm these results.

Keywords: Acute kidney injury; Burn critical care units; Length of stay; Multi-drug-resistant organisms.