A matched case-control study on Escherichia coli factors contributing to sepsis and septic shock in bacteraemic patients.

BACKGROUND

One third of patients with Escherichia coli bacteraemia develop a dysregulated inflammatory response (sepsis/septic shock). Our objective was to investigate whether specific microbiological determinants of E. coli are associated to presentation with sepsis/shock.

METHODS

A matched case-control study was performed; 101 case-patients with E. coli bacteraemia presenting with sepsis (SEPSIS-3 criteria) and 101 control-patients with E. coli bacteraemia without sepsis were matched by service, sex, age, Charlson index, acquisition and source of the bacteraemia and empirical treatment. Whole genome sequencing of E. coli isolates was performed (Illumina MiSeq Inc.). Sequence type, serotype, fimH type, virulence factors, antibiotic resistance genes, plasmid replicons pathogenicity islands and prophages were determined. A multivariate model was built for presentation with sepsis/septic shock using conditional logistic regression. The predictive capacity on the observed data was measured with the area under the ROC curve (AUROC) with 95% confidence intervals (CI).

RESULTS

Here we show that in the multivariate model (adjusted OR; 95% CI), the ST69 clone (7.53; 1.06-35.05) and pic gene (4.38; 1.53-12.54) are associated to presentation with sepsis/shock, while the genes papC (0.30; 0.12-0.74) and fdeC (0.18; 0.03-1.32) show a protective effect. The AUROC of this model is 0.81 (95% CI 0.74-0.87).

CONCLUSIONS

We identify E. coli bacterial factors associated with severe clinical presentation in patients with bacteraemia. Further studies would be needed to consider these factors as potential preventive or therapeutic targets.