Bloodstream Infections Due to Multidrug-Resistant Gram-Negative Organisms in Hematopoietic Stem Cell Transplant Recipients: A Multicenter Case-Control Study in a High-Prevalence Area.

BACKGROUND

Over the last decade, an alarming increase in multidrug-resistant gram-negative (MDR-GN) pathogens has been recorded at hematopoietic stem cell transplant (HSCT) centers around the world. Infections caused by MDR-GN bacteria not only lead to treatment failure and longer hospital stays but also result in high morbidity and mortality rates.

OBJECTIVE

To examine the incidence, risk factors, and outcomes of MDR-GN bacteremia among HSCT recipients in an area of high antimicrobial resistance.

STUDY

DESIGN

Patients with bacteremia from 7 Greek HSCT centers were prospectively enrolled and followed up for 12 months. We compared patients with MDR-GN bacteremia to those with non-MDR-GN bacteremia, gram-positive (GP) bacteremia and matched controls without bacteremia in terms of demographics, clinical features, microbiology, and outcomes.

RESULTS

In 523 HSCTs performed, we identified 142 episodes of bacteremia due to MDR-GN (38 patients), non-MDR-GN (37 patients), and GP pathogens (67 patients). The overall incidence of MDR-GN bacteremia was 1.4 per 1000 patient-days (95% confidence interval, 1.0-1.9), ranging from 0.0 to 2.9/1000 patient-days across participating centers (P = .01). When comparing patients with MDR-GN bacteremia to those with bacteremia caused by other organisms, in multivariate analysis, age and allogeneic HSCT were independent risk factors for MDR-GN bacteremia. The 12-month mortality rates were 34.5% in bacteremic patients, 60.5% for patients with MDR-GN, 32.4% with non-MDR-GN, and 20.9% with GP bacteremia (P < .001). MDR-GN bacteremia, relapse of the underlying disease, and GVHD were independent risk factors for death.

CONCLUSIONS

These findings highlight the importance of implementing rigorous infection control measures, in HSCT centers located in areas with high prevalence of antimicrobial resistance.