title: Prophylaxis with levofloxacin: impact on bacterial susceptibility and epidemiology in a hematopoietic stem cell transplant unit.
abstract: BACKGROUND
  The emergence of resistance has been demonstrated in cancer treatment centers where prophylaxis with fluoroquinolone is used.
  
  
  OBJECTIVE
  Considering the importance of epidemiological monitoring as a strategy in choosing protocols involving antibiotics, this study aimed to evaluate the emergence of quinolone resistance and changes in the local epidemiology in a hematopoietic stem cell transplant service.
  
  
  METHODS
  For this study, 60 positive cultures before the prophylactic use of levofloxacin (period A: 2007-2008) and 118 cultures after starting the use of prophylactic levofloxacin (period B: 2010-2011) were evaluated.
  
  
  RESULTS
  Resistance increased for all the different types of bacteria isolated (from 46.0% to 76.5%; p-value = 0.0002). Among Gram-negative bacteria, resistance increased from 21.4% to 60.7% (p-value = 0.0163) and among Gram-positive bacteria, it increased from 55.6% to 82.9% (p-value = 0.0025). The use of levofloxacin increased from 19.44 defined daily doses per 1,000 patient-days in period A to 166.64 in period B. The use of broad spectrum antibiotics remained unchanged. Considering bacteria associated with infection, 72 and 76 were isolated in periods A and B, respectively. There was a reduction in the rate of Gramnegative bacteria in cultures associated with infection (3.81 vs. 2.00 cultures/1,000 patientdays; p-value = 0.008).
  
  
  CONCLUSIONS
  The study of prophylaxis with levofloxacin demonstrated that there was a decrease in infections by Gram-negative bacteria; however, bacterial resistance increased, even though the use of broad-spectrum antibiotics remained unchanged. Constant monitoring of local epidemiology combined with research on clinical outcomes is needed to evaluate the effectiveness of prophylaxis.
authors.affiliation: Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors.forename: Livia Amaral Alonso
authors.initials: LA
authors.lastname: Lopes
authors.affiliation: Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors.forename: Izelândia
authors.initials: I
authors.lastname: Veroneze
authors.affiliation: Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors.forename: Célia Inês
authors.initials: CI
authors.lastname: Burgardt
authors.affiliation: Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
authors.forename: Christiane Johnscher
authors.initials: CJ
authors.lastname: Niebel Stier
keywords: Antibiotic prophylaxis; Drug resistance, bacterial; Fluoroquinolone; Hematopoietic stem cell transplantation