Prophylactic Levofloxacin Use in Oncology and Hematopoietic Stem Cell Transplants for Children Under 2 Years of Age

This study evaluates the efficacy and safety of levofloxacin (LVX) prophylaxis against bacteremia and febrile neutropenia in infants under 6 months of age compared with those 6 months to 2 years old with acute myeloid leukemia (AML), relapsed acute lymphoblastic leukemia (rALL), infant ALL (iALL), Down syndrome with ALL (DS ALL), or undergoing hematopoietic stem cell transplantation (HSCT). A retrospective chart review was conducted at Children's Mercy Hospital, Kansas City, MO (April 2019 to September 2024), including 79 encounters from patients receiving LVX prophylaxis. Data were collected on occurrences of bacteremia, febrile neutropenia, and adverse drug reactions. Bacteremia occurred in 9% of patient encounters with no significant difference between the infants under 6 months and the older age group ( P =0.643). Secondary outcomes of total duration of treatment antibiotic exposure and increases in liver enzymes were statistically different between groups. However, based on underlying differences in baseline characteristics, the results do not support definitive clinical significance. Other secondary outcomes, including febrile neutropenia, total LVX exposure, and time to first fever, showed no difference between groups. Of 7 positive blood cultures, susceptibility testing for LVX was performed for one culture isolate of Streptococcus mitis , and it was resistant to LVX. This preliminary data indicates that further research is needed in this underexplored topic to confirm these findings with larger patient populations and explore long-term safety in this vulnerable population.