Ciprofloxacin prophylaxis in allogeneic haematopoietic cell transplantation reduces bacteraemia but increases antimicrobial resistance without improving patient outcomes.

BACKGROUND

Fluoroquinolone prophylaxis during allogeneic haematopoietic cell transplantation (allo-HCT) is debated due to concerns regarding toxicity and antimicrobial resistance (AMR).

METHODS

We compared clinical and microbiological outcomes of all adults undergoing their first allo-HCT for haematological malignancy at two large UK transplantation centres between January 2020 and December 2022. The centres employed differing prophylactic strategies: Site 1 administered ciprofloxacin prophylaxis; Site 2 did not.

RESULTS

Among 343 eligible patients, primary allo-HCT indications were acute myeloid leukaemia (36.7%), acute lymphoblastic leukaemia (16.3%), myelodysplastic syndrome (11.1%). Bloodstream infections (BSIs) were less frequent at Site 1 (28.7%) than Site 2 (44.0%, P < 0.001), mainly due to fewer Gram-negative BSIs (15.3% vs 31.6%, P < 0.001). Multivariable analysis confirmed these findings (BSI odds ratio [OR] 4.06, 95% confidence interval [CI] 2.04-8.0; Gram-negative BSI OR 3.43, 95% CI 1.69-6.95). In-hospital mortality rates were not significantly different between the sites (7.3% at Site 1 vs 3.6% at Site 2, P = 0.15), nor were intensive care unit admissions (8.7% vs 8.3%, P ≥ 0.9), including in multivariable analysis. Enterobacterales BSIs at Site 1 exhibited higher resistance rates to ciprofloxacin (73.7% vs 18.5%), piperacillin-tazobactam (63.2% vs 16.7%), ceftriaxone (68.4% vs 18.5%), meropenem (15.8% vs 0%). Overall antibiotic usage, including carbapenems, was significantly higher at Site 1 (P < 0.001).

CONCLUSION

Ciprofloxacin prophylaxis was associated with a significant reduction in Gram-negative BSIs; however, it did not translate into differences in patient morbidity or mortality. Significantly higher levels of AMR were documented in breakthrough BSIs of patients receiving ciprofloxacin prophylaxis.