The role of colonization with resistant Gram negative bacteria in the treatment of febrile neutropenia after stem cell transplantation.

Introduction: Febrile neutropenia (FN) is one of the most common complications of stem cell transplantation. The aim of this analysis was to evaluate the frequency of sepsis in patients with FN colonized with resistant Gram negative bacteria (Extended spectrum β-lactamase positive, multidrug resistant (MDR) P. aeruginosa) and the choice of primary antibiotic in colonized patients.

Patients and methods: This was a retrospective study analyzed data from patients who underwent hematopoietic stem cell transplantation from 01/2018 to 09/2022. Data were extracted from the hospital information system.

Results: Carbapenem as the primary antibiotic of choice was chosen in 10.9% of non-colonized +/-AmpC patients, 31.5% of ESBL+ patients, and 0% of MDR P. aeruginosa patients. Patients with FN and MDR P. aeruginosa colonization had a high prevalence of sepsis (namely 100%, p = 0.0197). The spectrum of sepsis appeared to be different, with Gram negative bacilli predominating in the ESBL+ group (p = 0.0123, OR 5.39 [95% CI 1.55-18.76]). Colonizer sepsis was present in 100% of sepsis with MDR P. aeruginosa colonization (p=0.002), all in allogeneic transplantation (p=0.0003), with a mortality rate of 33.3% (p=0.0384). The incidence of sepsis in patients with ESBL+ colonization was 25.9% (p=0.0197), with colonizer sepsis in 50% of sepsis cases (p=0.0002), most in allogeneic transplantation (p=0.0003).

Conclusion: The results show a significant risk of sepsis in FN with MDR P. aeruginosa colonization, this state is almost exclusively caused by the colonizer. At the same time, a higher risk of Gram negative sepsis has been demonstrated in patients colonized with ESBL+ bacteria.