Bacterial blood stream infections negatively impact on outcome of patients treated with allogeneic stem cell transplantation: 6 years single-centre experience

Abstract

Background: Blood stream infections (BSIs) represent a major complication of allo-SCT and are a major cause of morbidity and mortality during and after bone marrow aplasia. Objectives: The objective of this study was to describe the incidence and outcome of BSIs in a cohort of patients submitted to allo-SCT, in order to track changes of the epidemiology and bacteria resistance. Methods: We retrospectively analyzed the microbiological data of 162 patients allotransplanted in Brescia University Hospital, over a period of 6 years. Results: Eighty patients experienced a BSIs for a total of 119 isolates. In 77 cases (65%) a Gram positive bacteria was isolated, being coagulase negative Staphilococci the most frequent species (77% of the cases). In 42 cases (35%) a Gram negative bacteria was isolated (E. coli 57% and P. aeruginosa 24%). Fluoroquinolones resistance was frequent (90% for S. epidermidis, 92% for E. coli, 90% for P. aeruginosa). Methycillin resistance of S. epidermidis was 100%, 76% of E. coli were ESBL positive and among P. aeruginosa resistance to carbapenems was 40%. The 2 years overall survival of patients with BSIs vs patients without BSIs was 46% vs 60% (HR1,48, p=0,07). P. aeruginosa and E. coli were the species with the highest mortality (50% and 33%, respectively). Conclusions: These data confirm that BSIs, mainly sustained by Gram positive bacteria, are frequent in allotransplanted patients (50% of the cases) and may influence the outcome of allotransplanted patients, being antibiotics resistance highly frequent among these bacteria.