Follow-up blood cultures in gram-negative bacilli bacteremia. Are they needed for critically ill patients?

BacKgroUnD: gram-negative bacilli bacteremias (gnB-Bs) represent a major cause of morbidity and mortality in intensive care Unit (icU) patients. aim of this study was to investigate the role of follow-up blood cultures (FUBcs) and the clinical significance of persistent bacteremia (PB) in these settings. MetHoDs: We retrospectively analyzed clinical data and outcome of gnB-Bs that occurred in icU patients over a span of 1 year. In particular we sought information on development and clinical details of PB, defined as repeatedly positive FUBCs after ≥96 hours of appropriate antibiotic treatment and ≥48 hours after removal of endovascular devices. resUlts: among 307 icU patients, 69 (22.4%) developed 107 gnB-Bs. of these, 78 (73%) could be eventually analyzed: 50 of 78 (64.1%) were non-PBs from 26 patients and 28 of 78 (35.9%) were PBs from 23 patients. Duration of fever and bacteremia, time to procalcitonin normalization and weaning from vasopressors were longer in episodes of PBs than non-PBs (P=0.04, P<0.001, P=0.02 and P=0.004, respectively). Primary bacteremia was more frequent in non-PBs than in PBs (29 of 50, 58% vs. 3/28, 10.7%, P=0.0001), whereas septic thrombus infection (sti) was the source of infection in 14 of 28 (50%). Finally, clinical features and 30-day mortality did not differ between patients with PB and those who developed only non-PB episodes. conclUsions: among our icU patients, more than one third of gnB-Bs for which FUBcs were performed resulted PB. this condition is often associated with the presence of sti; therefore, FUBcs seem useful for the optimal management of gnB in this clinical setting.