Background:Little is known on the burden of co-infections and superinfections in COVID-19 sub-intensive care units.

Aims and objectives:(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 study including COVID-19 patients with: (i) respiratory failure and/or ARDS; (ii) hospitalization in sub-intensive care unit. 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 superinfections were an independent risk factors for in-hospital mortality. CR-Ab resulted independently associated with 14-d mortality.

Conclusion:In a COVID-19 sub-intensive care unit superinfections represented an indipendent predictor of mortality.