Risk factors and effect on mortality of superinfections in a newly established COVID-19 respiratory sub-intensive care unit at University Hospital in Rome

BACKGROUND: Little is known on the burden of co-infections and superinfections in a specific setting such as the respiratory COVID-19 sub-intensive care unit. This study aims to (i) assess the prevalence of concurrent and superinfections in a respiratory sub-intensive care unit, (ii) evaluate the risk factors for superinfections development and (iii) assess the impact of superinfections on in-hospital mortality. METHODS: Single-center retrospective analysis of prospectively collected data including COVID-19 patients hospitalized in a newly established respiratory sub-intensive care unit managed by pneumologists which has been set up from September 2020 at a large (1200 beds) University Hospital in Rome. Inclusion criteria were: (i) COVID-19 respiratory failure and/or ARDS; (ii) hospitalization in respiratory sub-intensive care unit and (iii) age > 18 years. Survival was analyzed by Kaplan–Meier curves and the statistical significance of the differences between the two groups was assessed using the log-rank test. Multivariable logistic regression and Cox regression model were performed to tease out the independent predictors for superinfections’ development and for mortality, respectively. RESULTS: A total of 201 patients were included. The majority (106, 52%) presented severe COVID-19. Co-infections were 4 (1.9%), whereas 46 patients (22%) developed superinfections, mostly primary bloodstream infections and pneumonia. In 40.6% of cases, multi-drug resistant pathogens were detected, with carbapenem-resistant Acinetobacter baumannii (CR-Ab) isolated in 47%. Overall mortality rate was 30%. Prior (30-d) infection and exposure to antibiotic therapy were independent risk factors for superinfection development whereas the development of superinfections was an independent risk factors for in-hospital mortality. CR-Ab resulted independently associated with 14-d mortality. CONCLUSION: In a COVID-19 respiratory sub-intensive care unit, superinfections were common and represented an independent predictor of mortality. CR-Ab infections occurred in almost half of patients and were associated with high mortality. Infection control rules and antimicrobial stewardship are crucial in this specific setting to limit the spread of multi-drug resistant organisms. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12890-023-02315-9.