Predictive factors of ESBL versus non-ESBL Escherichia coli bacteraemia and influence of resistance on the mortality of the patients

Objective: To analyze predictor factors of extended-spectrum betalactamasa (ESBL)-producing E. coli and its repercussion in mortality.

Methods: Observational and comparative study of a cohort of non-paediatric admitted patients with E. coli bacteraemia (EB).

Results: 153 EB (22% ESBL-producing strains). Risk factors associated with ESBLB: previous antibiotic treatment (OR 2.61; 95% CI 1.1-6.19), severity Winston score ≤2 (OR 9.83, 95% CI 3.42-28.26) and health-related acquired infection (OR 5.35; 95% CI 1.57-18.27). Related mortality rate was 21%, being independent risk factors: cancer (OR 4.02; 95% CI 1.08-14.82), high severity of underlying disease (McCabe) (OR 7.69; 95% CI 1.96-30.09) and critical severity of illness at onset (Winston) (OR 48.89; 95% CI 11.58-206.97). Inappropriate empirical therapy was more frequent in EBSL-producing group (67%, p<0.05).

Conclusions: Previous antibiotic treatment, severity Winston score ≤2 and health-related acquisition are factors associated to ESBL EB. EBSL-producing strains or inadequate treatment were not associated to higher mortality. Factors statistically associated to mortality were cancer, severity of underlying diseases and critical severity of illness at onset.