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

Abstract

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: Bloodstream infection; CTX-M ESBL; Delayed definitive treatment; Early mortality; Escherichia coli; ST131.

Fig. 1

Flowchart for the case selection of E. coli bloodstream infection for analysis. Number of E. coli blood isolates and the bed size are indicated by hospital with a line-association of the district served by either in gray or in black. BSI, bloodstream infection.

Fig. 2

Genotypic and phenotypic diversity of E. coli blood isolates by six most strain types. The proportion of isolates having the geno/phenotype is indicated and statistical significance (P < 0.05) determined by Pearson's chi-square test is in bold. A smaller proportion compared to that of total is indicated in blue-gradients and a greater proportion than that of total is indicated in red-gradients. ST, sequence type; DS, drug-susceptible; DR, drug-resistant; MDR, multidrug resistance; ESBL, extended-spectrum beta-lactamase.