Retrospective analysis of positive blood cultures in patients in the emergency department

Abstract

We retrospectively analyzed the clinical features and characteristics of 557 patients with blood culture results. Patients were admitted to the emergency department of Chiba Aoba Municipal Hospital between January and December 2015. Of the 557 patients, blood cultures tested positive for bacteria in 75 patients (13.5%). Among the bacteria-positive blood culture isolates, the most common sites of infection were the urinary tract (34.7%), followed by the biliary tract (16.0%) and respiratory tract (10.7%). Among the 78 true-bacteria isolates, those frequently detected were Escherichia coli (28, 35.9%), Klebsiella pneumoniae (7, 9.0%), and Staphylococcus aureus (6, 7.7%); the frequency of isolating Enterobacteriaceae was high. Logistic regression analysis revealed that systemic inflammatory response syndrome (SIRS), diastolic blood pressure (DBP), and total bilirubin (T-Bil) and creatinine (Cr) levels were reliable predictive factors for bacteria-positive blood cultures. Patients with bacteria-positive blood cultures also had poorer outcomes than those with bacteria-negative blood cultures; albumin (Alb) and lactate (Lac) levels were found to be related to hospital mortality. The area under the receiver-operating characteristic curve (AUC) demonstrated that the value predicted using logistic regression analysis employing SIRS, DBP, and T-Bil and Cr levels were accurate (AUC = 0.79 [95% confidence interval: 0.74–0.84]). In the present study, the clinical features of patients with bacteria-positive blood cultures were revealed. These results are helpful for early diagnosis and quick planning for treatment.