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The following is a summary of “Burden of nosocomial superinfections in a retrospective cohort study of critically ill COVID-19 patients,” published in the May 2025 issue of BMC Infectious Diseases by Lösslein et al. 

Viral respiratory infections, including those caused by SARS-CoV-2, were found to be complicated by bacterial superinfections, and changes in the study cohort over time due to patient discharge or death could distort the assessment of superinfection impacts.  

Researchers conducted a retrospective study to analyze superinfections in patients with critical illness, considering the discharge and death as competing risks in the statistical analysis.  

They evaluated bacterial respiratory infections and bloodstream infections in 268 patients with critical illness, using multi-state statistical modeling to account for various patient states. Risks of superinfection, as well as the probability of discharge or death over time, were calculated. The analysis also included subgroup evaluations based on age and sex.  

The results showed that the pathogen spectrum primarily consisted of Enterobacterales, Nonfermenters, and Staphylococcus aureus. Bacterial infections of the respiratory tract or bloodstream were associated with increased mortality (adjusted cause-specific hazard ratio (HR) 1.7, CI 1.15–2.52) and a reduced discharge rate (adjusted cause-specific HR 0.51, CI 0.36–0.73). Female patients had a lower risk of acquiring a superinfection (adjusted subdistribution HR 0.71, CI 0.48–1.04), but in the cases of infection, they experienced higher mortality than male patients (interaction effect HR 1.49, CI 0.67–3.30).  

Investigators concluded that the study accounted for competing risks and highlighted an increased risk of death associated with the bacterial superinfection in critically ill patients with COVID-19, with Enterobacterales being the predominant pathogen, underscoring the need for microbiological sampling in patients infected with SARS-CoV-2. 

Source: bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-025-10983-7