Changing epidemiology, microbiology and mortality of bloodstream infections in patients with haematological malignancies before and during SARS-CoV-2 pandemic: a retrospective cohort study.

Objective: This study was to explore the changes in bacterial bloodstream infection (BSI) in patients with haematological malignancies (HMs) before and during SARS-CoV-2 pandemic.

Design: Retrospective cohort study between 2018 and 2021.

Setting: The largest haematological centre in southern China.

Results: A total of 599 episodes of BSI occurring in 22 717 inpatients from January 2018 to December 2021 were analysed. The frequencies of the total, Gram-negative and Gram-positive BSI before and during the pandemic were 2.90% versus 2.35% (p=0.011), 2.49% versus 1.77% (p<0.001) and 0.27% versus 0.44% (p=0.027), respectively. The main isolates from Gram-negative or Gram-positive BSI and susceptibility profiles also changed. The 30-day mortality caused by BSI was lower during the pandemic (21.1% vs 14.3%, p=0.043). Multivariate analysis revealed that disease status, pulmonary infection and shock were independent predictors of 30-day mortality.

Conclusion: Our data showed that the incidence of total and Gram-negative organisms BSI decreased, but Gram-positive BSI incidence increased in patients with HMs during the pandemic along with the changes of main isolates and susceptibility profiles. Although the 30-day mortality due to BSI was lower during the pandemic, the new infection prevention strategy should be considered for any future pandemics.