Mortality caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae bacteremia; a case control study: alert to Enterobacteriaceae strains with high minimum inhibitory concentrations of piperacillin/tazobactam.

This study aimed to assess the prognostic factors of patients with bacteremia due to extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) as well as the antimicrobial susceptibility, particularly to piperacillin/tazobactam (PTZ), among ESBL-PE strains. The medical records of 65 patients with ESBL-PE bacteremia divided into the survivor group (n = 52) and nonsurvivor group (n = 13) were retrospectively reviewed. The male-to-female ratio, age, underlying disease, leukocyte count, C-reactive protein level, and treatment did not differ between the 2 groups. Multivariate analysis showed that the independent predictors associated with hospital mortality of ESBL-PE bacteremia were sepsis (P = 0.047) and febrile neutropenia (P = 0.008); thus, early assessment of these conditions is important. Further, the minimum inhibitory concentration values of ESBL-PE isolates in nonsurvivors tended to be higher than those in survivors. PTZ should be used with caution in cases of ESBL-PE strains with low susceptibility to the drug.