Infections complications are the major causes of morbidity and mortality in hematopoietic stem cell transplantation (HSCT) (
1).
Even though the risk of death due to infection is much lower after autologous transplantation (compared to allogeneic transplantation). The risks of procedure are greater than those of conventional chemotherapy, and preventive policies should be implemented in any transplant program. Because of the hospital environment and bacterial resistance, the physical environment of transplant patients should aim to decrease the risk of nosocomial infection (
2).
The gut is the main reservoir for gram-negative bacteria and a source of subsequent entry into the body. Gut decontamination is approached in different centers and countries. The fluoroquinolones, introduced in the 1980s, have transformed this field, becoming the most commonly used prophylactic antibacterial agents in neutropenic patients because of their broad antimicrobial spectrum, preservation of anaerobic gut flora, systemic bactericidal activity, good tolerability and lack of myelosuppression. In acute leukemia patients, a large trial comparing levofloxacin to placebo has shown that the use of levofloxacin during neutropenic phase significantly reduces the risk of fever, bacterial infection, bacteremia, especially of gram-negative infections, and cost of intravenous antibacterial medicine for febrile neutropenia (
3,
4,
5,
6,
7 and
8). The medicine should be given until the first febrile episode or the recovery of neutropenia in the absence of fever. There is no doubt that routine prophylactic use of antibiotics can cause colonization of an individual patient with resistant organisms; but, the clinical relevance of this is unclear. Before 2005, few trials had been performed and none were large enough to provide conclusive evidence on the benefit of prophylaxis (
9,
10,
11,
12 and
13). Bucaneve
et al. (2005) observed a non-significant increase in the incidence of levofloxacin-resistant gram-negative bacteremia among patients receiving levofloxacin, but this did not affect outcomes such as infection-related morbidity or mortality. Therefore, their use is not recommended in units with a high level of quinolone resistance among gram negative bacteria and should be associated with periodic monitoring of local epidemiology as well. (
14).