Epidemiology and risk factors for mortality in bloodstream infections: A single-center retrospective study in Japan.

Background: Few published data are available on the morbidity and mortality of bloodstream infections (BSIs) in Japan. We sought to investigate the epidemiology of BSIs, the involvement of antimicrobial resistance, and the factors that influence patient prognosis.

Methods: This single-center study retrospectively evaluated patients who were found to have positive blood cultures at a tertiary teaching hospital between January 2012 and December 2016.

Results: A total of 2,105 patients with BSIs were included; 1,786 survived and 319 died, and the 30-day mortality rate was 15.2% over the 5-year study period. BSIs caused by yeasts were independently associated with 30-day mortality. The 30-day mortality rate of BSIs caused by extended-spectrum beta lactamase-producing gram-negative bacteria was significantly higher than that of BSIs caused by nonproducing bacteria.

Discussion: The differences in mortality may be caused by differences in the distribution of pathogens and in the delivery of health care.

Conclusions: This study reported epidemiology and antimicrobial resistance data of BSIs in Japan and identified several risk factors associated with 30-day mortality. National surveillance of BSIs is required in Japan for comparison with other countries.