Clinical and microbiological impact of discontinuation of fluoroquinolone prophylaxis in patients with prolonged profound neutropenia

Background Infections remain a leading cause of morbidity and mortality in patients with reduced immunity caused by haematological disease and chemotherapy‐induced neutropenia. We evaluated the clinical and microbiological impact of discontinuing fluoroquinolone prophylaxis in these patients. Methods We analysed 154 admissions in three sequential periods of 8 months: long‐standing use, discontinuation of prophylaxis and reintroduction of prophylaxis. Clinical endpoints were occurrence of febrile neutropenia, bacteraemia, severe sepsis, septic shock, response to antibiotic therapy, total antibiotic consumption and duration of hospital stay. Microbiological analysis included bacterial isolates from stool and blood cultures and their resistance pattern. Results No significant increase in serious infectious complications was seen with the discontinuation of prophylaxis. The overall incidence of bacteraemia did not change, but a higher proportion of bacterial isolates were Gram‐negative (22.2% vs. 5.9% & 8.6%; P = 0.030), more often multisusceptible (50% vs. 0%) and less fluoroquinolone resistant (10% vs. 100%). Screening of stools showed a higher prevalence of organisms in the discontinuation period (86.7% vs. 37.3% & 55.2%; P ≤ 0.001), but they were more frequently multisusceptible (53.8% vs. 10.5% & 6.3%; P ≤ 0.001). After discontinuation of prophylaxis, fluoroquinolone resistance decreased rapidly from 73.7 to 7.7%, in association with a significant decrease in extended spectrum beta‐lactamase (ESBL)‐producing isolates from 42.1 to 10.3%. Resistance figures immediately returned to prediscontinuation values after reinstitution of prophylaxis. Conclusions No clinically relevant short‐term drawbacks were observed with the discontinuation of fluoroquinolone prophylaxis in patients with chemotherapy‐induced prolonged profound neutropenia, which led to a significant decrease in fluoroquinolone resistance as well as occurrence of ESBL‐producing isolates.