Higher mortality was observed in patients with Pseudomonas aeruginosa (PA) bloodstream infection (PA-BSI) and COVID-19 co-infection, researchers reported today in Antimicrobial Stewardship & Healthcare Epidemiology.
Using data on patients in the Veterans Health Administration system, researchers from Case Western Reserve University assessed all-cause mortality in patients with PA-BSI and concomitant COVID-19 infection, comparing the pre-COVID-19 period (January 2009 to December 2019) with the COVID-19 period (January 2020 to June 2022). Patients in the COVID-19 period were further stratified by the presence or absence of COVID-19 coinfection. Previous studies have suggested a rise in PA-BSI incidence with the onset of the COVID-19 pandemic, but outcomes of patients with PA-BSI and COVID-19 coinfection have not been evaluated.
A total of 6,714 patients with PA-BSI were identified. Throughout the study period, PA resistance rates decreased. Thirty-day all-cause mortality decreased pre-COVID-19 and increased during COVID-19. Mortality was not significantly different between pre-COVID-19 (24.5%; 95% confidence interval [CI], 23.3 to 28.6) and the COVID-19 period/COVID-negative (26.0%; 95% CI, 23.5 to 28.6) patients, but it was significantly higher in COVID-19 period/COVID-positive patients (47.2%; 95% CI, 35.3 to 59.3).
After adjusting for potential confounders, the modified Poisson analysis showed that COVID-19 coinfection was associated with a 44% higher death rate (relative risk, 1.44; 95% CI 1.01 to 2.06). Higher Charlson Comorbidity Index, higher modified Acute Physiology and Chronic Health Evaluation score, and no targeted PA-BSI treatment within 48 hours were also predictors of higher mortality.
Potential synergy between the 2 infections
The study authors suggest several factors could account for increased mortality among patients coinfected with PA-BSI and COVID-19, including pandemic-related staffing shortages and limited availability of infectious diseases expertise. But they also say further research is needed on the interaction between the two infectious processes.
"The relationship between COVID-19 and PA should be explored in more detail to determine whether characteristics of either pathogen enhance the infectivity of the other or work synergistically against the host immune response, and inclusion of observations of patients with COVID-19 with and without PA-BSI could be helpful to this end," they wrote.