The aim of this study is to clarify the characteristics of gram-negative bacteremia (GNB), including extended-spectrum β-lactamase (ESBL)-producing pathogens, among allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients on levofloxacin (LVFX) prophylaxis. A retrospective analysis on GNB at the first episode of febrile neutropenia (FN) was conducted among allo-HSCT recipients (age ≥ 20 years) on 500 mg/day of oral LVFX prophylaxis. Epidemiological and microbiological features of GNB were investigated and compared between the inappropriate and appropriate empiric therapy groups. In total, FN occurred in 414 allo-HSCT cases, and bacteremia at the first episode of FN occurred in 169 cases. Overall, 29 GNB cases were documented, and the causative organisms identified were Escherichia coli in 21 cases (including 10 ESBLs), Klebsiella pneumoniae in 2, Pseudomonas aeruginosa in 2, and other in 4. The crude 30-day mortality rate was not significantly different among cases of GNB (6.9%), gram-positive bacteremia (GPB) (7.1%), or non-bacteremia (5.4%; P = 0.78). Cefepime (CFPM) was administered in all cases in the inappropriate empiric therapy group, and all causative organisms were ESBL-producing E. coli (ESBL-EC). All patients in the inappropriate empiric therapy group had a low Pitt bacteremia score (≤ 2). Thirty-day mortality did not differ significantly between the inappropriate and appropriate empiric therapy groups (1/10 vs. 1/15, P = 0.61). In conclusion, GNB was not a significant cause of death. In LVFX breakthrough ESBL-EC bacteremia among allo-HSCT recipients, the administration of CFPM as empiric therapy did not lead to significantly poor prognosis. Empiric CFPM administration might be an acceptable strategy.

本研究的目的是阐明接受左氧氟沙星 (LVFX) 的异基因造血干细胞移植 (allo-HSCT) 受者中革兰氏阴性菌血症 (GNB) 的特征，包括产超广谱 β-内酰胺酶 (ESBL) 的病原体。预防。对异基因造血干细胞移植受者（年龄 ≥ 20 岁）在 500 mg/天口服 LVFX 预防性治疗中首次出现发热性中性粒细胞减少症 (FN) 时的 GNB 进行了回顾性分析。在不适当和适当的经验性治疗组之间调查和比较了 GNB 的流行病学和微生物学特征。共414例allo-HSCT病例发生FN，169例FN首次发作时出现菌血症。总共记录了 29 例 GNB 病例，确定的病原体为大肠杆菌21例（含10例ESBLs），肺炎克雷伯菌2例，铜绿假单胞菌2例，其他4例。GNB（6.9%）、革兰氏阳性菌血症（GPB）30天粗死亡率无显着差异) (7.1%) 或非菌血症 (5.4%; P  = 0.78)。不适当经验性治疗组的所有病例均给予头孢吡肟（CFPM），所有致病菌均为产 ESBL 的大肠杆菌（ESBL-EC）。不适当经验性治疗组的所有患者的 Pitt 菌血症评分均较低（≤ 2）。不适当和适当经验性治疗组之间的 30 天死亡率没有显着差异（1/10 对 1/15，P = 0.61）。总之，GNB 不是一个重要的死亡原因。在同种异体造血干细胞移植受者的 LVFX 突破性 ESBL-EC 菌血症中，使用 CFPM 作为经验性治疗并未导致明显的不良预后。经验性 CFPM 管理可能是一种可接受的策略。