Immunosuppression Linked to Higher Blood Infection Mortality

When bloodstream infections strike patients who are immunocompromised, the danger does not just stem from ordinary bacteria. According to data reported by Open Forum Infectious Diseases, these infections more often involve opportunistic pathogens like Enterococcus faecium and Pseudomonas species, carrying a higher risk of death than infections in immunocompetent patients.

The study, led by Oskar Ljungquist of the Faculty of Medicine at Lund University in Sweden, looked at how underlying immunosuppression alters both the course and the lethality of bloodstream infections. Researchers examined 47,552 bloodstream infection episodes across nine acute care hospitals in Skåne, Sweden, tracking patient outcomes between May 2013 and December 2023.

Rising Prevalence in Hospital Data

Over the study period, the share of bloodstream infections tied to underlying immunosuppression climbed. Out of the 47,552 bloodstream infection episodes, 8,058 cases—16.9%—occurred in patients with underlying immunosuppression. That proportion rose from 15.0% to 18.2% as the years progressed.

Patients with immunosuppression faced higher odds of contracting specific hard-to-treat bugs. The odds ratio for encountering Enterococcus faecium hit 2.62, while the odds for Pseudomonas species climbed to 2.24 compared to immunocompetent patients. Furthermore, intrinsic resistance to cefotaxime appeared more often in the immunosuppressed group, with an odds ratio of 1.45, with the highest rates of resistance being observed in neutropenia and healthcare-associated episodes.

Immunosuppression Increases Risk of Fatal Outcomes

The shift in pathogen profiles translates into a higher risk of fatal outcomes. Immunosuppression was linked to higher odds for mortality, registering odds ratios of 1.24 for 7-day mortality and 1.54 for 30-day mortality. Within the immunosuppressed cohort, 30-day mortality was the highest in patients receiving antineoplastic treatment and those with neutropenia and lower in transplant recipients.

From the clinical perspective, our findings suggest vigilance of resistant pathogens when choosing empirical treatment for immunosuppressed patients with suspected BSI. Broad empirical antimicrobial treatment should especially be considered in healthcare-associated BSIs, particularly in patients having received previous antimicrobial treatment.

the authors wrote in their published findings. While the retrospective design relied on diagnostic codes and medication data that could introduce selection bias—and left out certain at-risk groups like dialysis patients and those receiving corticosteroids—the Skåne surveillance data highlights changes in acute hospital care.

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