Abstract
BACKGROUND: Escherichia coli is the Gram-negative organism most commonly associated with bloodstream infections and death due to sepsis. Timely administration of appropriate antibiotic(s) plays a significant role in improving patient outcomes. E. coli expresses virulence factors (VFs) such as biofilm formation and motility phenotypes which play a role in bacterial attachment and dissemination by enabling immune system evasion and host migration. The role of these VFs in bacteremia prognosis is not well characterized. Our study aims to evaluate the clinical characteristics and outcomes of E. coli bacteremia patients specifically in relation to biofilm forming isolates. METHODS: 91 E. coli bacteremia clinical isolates were consecutively collected from patients between 2013 to 2015. Virulence factor phenotypes were determined by in vitro biofilm formation, motility, and milk hydrolysis. Clinical patient data associated with the isolates were abstracted from the electronic medical records database and blinded from research team throughout characterization. Descriptive statistics were used for clinical variables and analyzed in a dichotomized fashion based on biofilm formation. The chi-square or Fisher exact test were used for categorical data and the Mann–Whitney U or Student T-test for continuous variables as appropriate. RESULTS: Of the 91 isolates, 41 had a biofilm-forming phenotype. Of the 87 isolates tested for milk hydrolysis and motility a positive finding was seen in 61 (70%) and 67(77%) isolates, respectively. In the multivariate model, patients with E.coli bacteremia from biofilm producing isolates were at increased risk of death or going into hospice during that hospitalization. ([OR],9.8; 95% CI, 1.1,88.7, P = 0.041) CONCLUSION: Patients with biofilm-forming E. coli bacteremia had worse clinical outcomes than their non-biofilm forming counterparts suggesting that this phenotype leads to a more pathogenic organism. A prospective study to confirm this finding is needed as is the design of rapid diagnostics to promptly identify this phenotype in septic patients. DISCLOSURES: All authors: No reported disclosures.