Epidemiology and outcome of occult bacteremia in patients discharged from emergency departments or ambulatory units: one-year study.

Microbiological diagnosis of bloodstream infection (BSI) is made several hours after blood culture sampling. This delay could be critical in ambulatory clinics, emergency departments, and hospital day care units, as the patient may be discharged prior to blood culture positivity. Our aim was to evaluate the clinical outcome (including the number of readmissions) of patients diagnosed with BSI after discharge. We prospectively included all adult patients with positive blood culture for BSI that was confirmed after discharge from our center (Grenoble-Alpes University Hospital) in 2016. Patients were contacted about their blood culture results, and their clinical status was controlled via an external consultation or their family physician, with hospital readmission if necessary. Clinical outcome, accuracy of initial diagnosis, microbiological epidemiology, and antibiotic prescription were assessed. In 2016, 1433 episodes of positive blood culture were detected in our hospital, with 50 (3.5%) occurring after patient discharge. Clinically relevant bacteria were determined in 32/50 cases (64%), while other positive blood culture results were considered to be contaminants. Clinical reevaluation was performed in 45 patients (90%). The diagnosis was changed during the clinical reassessment of 24/49 patients (49%). Antibiotics were prescribed prior to discharge for 24/50 patients (48%), modified during follow-up for 15/45 (33%), and initiated for 13/45 (29%) at the reevaluation. Overall, 24/45 (53%) patients were readmitted to hospital units after reevaluation. The clinical follow-up of patients with positive blood culture after discharge led to diagnostic changes and hospital readmission in around half of patients.