Bloodstream infections: trends and evolution of incidence and etiology in a 12-year period (2010-2021)

The epidemiological evolution of bloodstream infections (BSIs) in the last decade is not clearly defined. Our aim was to analyze the changes in the workload in our institution and to describe the evolution of the incidence and etiology of BSIs in a 12-year period, including the COVID-19 pandemic.

All blood cultures received in the laboratory of a tertiary general hospital between 2010 and 2021 were analyzed. Bloodstream infection episodes refer to each episode of bacteremia or fungemia in each patient. Incidence rates per 1000 admissions and per 100,000 population were calculated.

No significant changes in the incidence of BSI episodes/1000 admissions were observed (mean, 31.1), while estimated population-based incidences showed declining trends (mean, 182.8/100,000 inhabitants). There was a slight increase in BSI episodes per 1000 admissions caused by Gram-negatives (mean, 16.6/1000 admissions) and E. coli was the most frequent pathogen (mean, 8.5/1000 admissions). There was no significant rise in episodes caused by ESBL- and carbapenemase-producing E. coli or K. pneumoniae, with a decline in those caused by methicillin-resistant S. aureus. A spike in BSI episodes, fungal BSIs and catheter-related infections was detected in 2020, during the COVID-19 outbreak.

No clear increase in the incidence of BSI episodes was detected in our center over this period. Gram-negatives are the most frequent etiology, with no clear rise in antimicrobial resistance phenotypes. The COVID-19 pandemic accounted for a small increase in BSI episodes in 2020, probably related to the increase of catheter-related infections.