Prophylaxis with levofloxacin: impact on bacterial susceptibility and epidemiology in a hematopoietic stem cell transplant unit.

backgroundThe emergence of resistance has been demonstrated in cancer treatment centers where prophylaxis with fluoroquinolone is used.

objectiveConsidering 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.

methodsFor 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.

resultsResistance 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).

conclusionThe 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.