Blood stream infections after allogeneic stem cell transplantation: a single-center experience with the use of levofloxacin prophylaxis.

Blood stream infections (BSIs) remain one of the major causes of morbidity and mortality for patients receiving an allogeneic hematopoietic stem cell transplantation (HSCT). In the present study, we evaluated the incidence and characteristics of BSI within 1 year after allogeneic HSCT in 269 consecutive adult patients who received antibacterial prophylaxis with levofloxacin. Cumulative incidence of BSI was 12% (95% confidence interval, 8-16%). Bacteria were responsible for 30 out of the 32 BSI, while fungi were responsible for 2 episodes of BSI. The median onset of BSI was day 8 (range 1-328 days) post transplant, and 66% of BSI occurred before neutrophil recovery. Gram-positive organisms accounted for 60% (n=18) of bacteremia, and gram-negative isolates for 40% (n=12) of the cases. Coagulase-negative staphylococci were the most commonly isolated gram-positive pathogens (53% of the cases), while Escherichia coli was the most commonly isolated gram-negative bacteria (58% of the cases). Candida albicans and Candida guillermondii were isolated from patients with candidemia. Resistance to fluoroquinolones (FQ) was common with 13% of gram-positive isolates being susceptible to FQ, while 50% of the gram-negative rods were susceptible to FQ. Crude mortality and mortality attributable to BSI were both 3% (1 of 32). In conclusion, our data suggest that despite the emergence of antibiotic resistance, FQ prophylaxis may be considered an appealing approach in allogeneic HSCT recipients and is also worth evaluating in randomized studies.