Impact of host-pathogen-treatment tripartite components on early mortality of patients with Escherichia coli bloodstream infection: Prospective observational studyResearch in context

Background: Risk factors affecting early morality of patients with Escherichia coli bloodstream infection (BSI) were investigated including the host-pathogen-treatment tripartite components. Methods: Six general hospitals in South Korea participated in this multicentre prospective observational study from May 2016 to April 2017 and a total of 1492 laboratory-confirmed E. coli BSI cases were studied. Cox regression was used to estimate risks of the primary endpoint, i.e., all-cause mortality within 30 days from the initial blood culture. Six multivariate analysis models were constructed in accordance to the clinical importance and intra- and inter-component multicollinearity. Findings: Among the 1492 E. coli BSI cases, 9.5% (n = 141) patients expired within 30 days. Six models of multivariate analysis indicated risk factors of critical illness, primary infection of peritoneum, and chronic liver disease including cirrhosis for host variables; of phylogenetic group B2, ST131-sublineage H30Rx, multidrug resistance, group 1 CTX-M extended-spectrum beta-lactamase production, and having either of fyuA, afa, and sfa/foc virulence genes for causative E. coli pathogen variables; and of delayed definitive therapy for antimicrobial treatment variables. In addition, as a protective factor, primary urinary tract infection was identified. Interpretation: Despite decades' effort searching for the risk factors for E. coli BSI, systemic understanding covering the entire tripartite component is still lacking. This study detailed the organic impact of host-pathogen-treatment tripartite components for early mortality in patients with E. coli BSI. Keywords: Escherichia coli, Bloodstream infection, Early mortality, ST131, CTX-M ESBL, Delayed definitive treatmen