Unique characteristics of community-onset healthcare- associated bloodstream infections: a multi-centre prospective surveillance study of bloodstream infections in Japan.

BACKGROUND: Analysis of bloodstream infections (BSIs) is valuable for their diagnosis, treatment and prevention. However, limited data are available in Japan.

AIM: To investigate the characteristics of patients with bacteraemia in Japan.

METHODS: This study was conducted in five hospitals from October 2012 to September 2013. Clinical, demographic, microbiological and outcome data for all blood-culture-positive cases were analysed.

FINDINGS: In total, 3206 cases of BSI were analysed: 551 community-onset healthcare-associated (CHA)-BSIs, 1891 hospital-acquired (HA)-BSIs and 764 community-acquired (CA)-BSIs. The seven- and 30-day mortality rates were higher in patients with CHA- and HA-BSIs than in patients with CA-BSIs. The odds ratios (ORs) for seven-day mortality were 2.56 [95% confidence interval (CI) 1.48-4.41] and 2.63 (95% CI 1.64-4.19) for CHA- and HA-BSIs, respectively. The ORs for 30-day mortality were 2.41 (95% CI 1.63-3.57) and 3.31 (95% CI 2.39-4.59) for CHA- and HA-BSIs, respectively. There were 499 cases (15.2%) of central-line-associated BSI and 163 cases (5.0%) of peripheral-line-associated BSI. Major pathogens included coagulase-negative staphylococci (N = 736, 23.0%), Escherichia coli (N = 581, 18.1%), Staphylococcus aureus (N = 294, 9.2%) and Klebsiella pneumoniae (N = 263, 8.2%). E. coli exhibited a higher 30-day mortality rate among patients with HA-BSIs (22.3%) compared with patients with CHA-BSIs (12.3%) and CA-BSIs (3.4%). K. pneumoniae exhibited higher 30-day mortality rates in patients with HA-BSIs (22.0%) and CHA-BSIs (22.7%) compared with patients with CA-BSIs (7.8%).

CONCLUSION: CHA- and HA-BSIs had higher mortality rates than CA-BSIs. The prognoses of E. coli- and K. pneumonia-related BSIs differed according to the category of bacteraemia.