Clinical characteristics and outcome of critically ill patients with bacteremia caused by extended-spectrum β-lactamase-producing and non-producing Escherichia coli

The number of patients infected with extended-spectrum beta-lactamase (ESBL)-producing organisms has increased dramatically worldwide, and high mortality rates are seen in severely ill patients. This study retrospectively compared the clinical characteristics and outcomes of critically ill patients in an intensive care unit (ICU) at the Tsuyama Chuo Hospital (Okayama, Japan) who were hospitalized for bacteremia caused by ESBL-producing Escherichia coli (ESBL-EC) or non-ESBL-producing E. coli (non-ESBL-EC) between January 2006 and December 2016 (11 years). We analyzed the patients' age, sex, underlying disease(s), sequential organ failure assessment scores, primary focus of bacteremia, empiric antibiotics, rate of appropriateness of empiric antibiotics, and treatment duration, with 28-day mortality being the primary outcome. The study included 24 patients with ESBL-EC bacteremia and 77 with non-ESBL-EC bacteremia. The rate of appropriate initial antibiotic treatment was significantly lower (54.2% vs. 96.1%, respectively; P < 0.01) and the mortality due to bacteremia significantly higher (37.5% vs. 15.6%, respectively; P = 0.04) in the ESBL-EC than in the non-ESBL-EC bacteremia group. A subgroup analysis focusing on patients who were administered appropriate empiric antibiotics showed that the 28-day mortality rate did not differ significantly between the two groups (P = 0.23). To our knowledge, this is the first study to compare the outcomes of patients with ESBL-EC and non-ESBL-EC bacteremia in a Japanese ICU setting. Initial empiric antibiotic therapy covering ESBL-producing pathogens should be considered for critically ill patients in the ICU.