Objective: The present study assessed risk factors and patient outcomes of bloodstream infection (BSI) caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli  (E. coli ).
Methods: A retrospective study was performed to analyze risk factors and patient outcomes of BSI caused by extended-spectrum β-lactamase-producing Escherichia coli  (ESBL-EC) in one Chinese tertiary hospital over a 7.5-year period. The clinical characteristics of patients infected with ESBL-producing and non-ESBL-producing E. coli  were compared. Predictors of 30-day mortality in patients with E. coli  BSI were also identified in our study.
Results: The results of drug sensitivity showed that quinolones, aminoglycosides, β -lactam/β -lactamase inhibitor combinations (BLICs) and trimethoprim/sulfamethoxazole exhibited significant differences between the ESBL and non-ESBL groups. Of the 963 patients with E. coli  BSI, 57.6% developed ESBL-EC. Multivariate analysis showed that biliary tract infection (BTI) [P< 0.001,OR (95% CI):1.798 (1.334– 2.425)], urinary tract obstructive disease [P=0.001,OR (95% CI):2.106 (1.366– 3.248)], surgery within 3 months [P=0.002,OR (95% CI):1.591 (1.178– 2.147)], hospitalization within 3 months [P< 0.001,OR (95% CI):2.075 (1.579– 2.725)], ICU admission [P=0.011,OR (95% CI):1.684 (1.124– 2.522)] and history of cephalosporin use [P=0.006,OR (95% CI):3.097 (1.392– 6.891)] were statistically significant. In mortality analysis, aCCI> 2 [P=0.016,OR (95% CI): 2.453 (1.179– 5.103)], gastrointestinal catheterization [P=0.004, OR (95% CI): 2.525 (1.333– 4.782)] were significantly associated with 30-day mortality. According to Kaplan-Meier survival analysis, we found that in SOFA< 2 group and SOFA≥ 2 group, the mortality rate of patients treated with BLICs were lower than that of carbapenems(P< 0.05).
Conclusion: This study showed that BTI, urinary tract obstructive disease, surgery within 3 months, hospitalization within 3 months, ICU admission and cephalosporin exposure were independent risk factors for the emergence of ESBL-EC BSI. Analysis of risk factors for 30-day mortality revealed that the factors independently associated with a higher risk of mortality were aCCI> 2, gastrointestinal catheterization. Compared to carbapenems, the BLICs had preferable effect to treat patients with ESBL-EC BSI. Notably, patients with severe illness were inlcined to use carbapenems, which affected the analysis results. Therefore, we suggest that BLICs could be recommended to treat mild patients with ESBL-EC bacteremia.
Keywords: Escherichia coli , extended-spectrum beta-lactamase, bloodstream infection, risk factors, carbapenems