The Impact of Modifying Empirical Antibiotic Therapy Based on Intestinal Colonization Status on Clinical Outcomes of Febrile Neutropenic Patients

BACKGROUND: This paper aimed to inspect factors affecting febrile neutropenia patients with hematologic malignancies. The intestinal colonization rate of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) and carbapenem-resistant Enterobacteriaceae (CRE) was assessed. The rate of subsequent ESBL-E and CRE bacteremia correlated with corresponding bacterial colonization was evaluated. Further, the risk factors for ESBL-E and CRE intestinal colonization were examined. Finally, the impact of rectal swab screening combined with adapted empirical antibiotic therapy on the mortality rate of patients with febrile neutropenia was assessed. MATERIALS AND METHODS: Febrile neutropenia patients underwent rectal swabs and collection of blood culture specimens upon admission. Empirical treatment was subsequently modified according to rectal swab results if necessary. Bacteremia patients were treated according to blood culture results. Explorative forward-stepwise logistic regression analyses were used to identify risk factors for ESBL-E and CRE fecal carriage and mortality. RESULTS: In total, 201 rectal swabs and 402 blood samples were collected from 163 patients during 201 febrile neutropenia episodes. Of these episodes, 38 (18.90%) were colonized with ESBL-E and 30 (14.92%) with CRE. Bloodstream infections developed in 29/201 (14.42%) episodes. Only bacteremia episodes caused by Gram-negative bacilli were included in our analysis. The development of Gram-negative-rod bacteremia was observed in eight out of 38 (21.05%) ESBL-E colonized episodes and four out of 30 (13.33%) CRE-colonized episodes. A BSI developed in three out of 38 (7.89%) ESBL-E colonized episodes, and two out of 30 (6.66%) CRE-colonized episodes developed BSI with the respective organism. Multivariate analysis identified previous quinolone use as the only independent risk factor for fecal colonization of multi-drug-resistant (MDR) Enterobacteriaceae (ESBL-E and CRE) (odds ratio, 17.09; 95% confidence interval, 5.29 - 55.18; P <0.0001). No significant association was observed between ESBL-E and CRE carriage and increased risk of developing subsequent bacteremia. No significant differences were detected between groups receiving modified and non-modified treatments in duration of hospitalization or antibiotic therapy (univariate analysis) and 28-day mortality rate (logistic regression). CONCLUSION: Quinolone exposure was a major risk factor for ESBL-E and CRE fecal carriage. Performing rectal swab screening for MDR Enterobacteriaceae and modifying empirical antibiotic therapy accordingly did not improve clinical outcomes of febrile neutropenia patients.