Nosocomial bloodstream infections in a Finnish tertiary care hospital: a retrospective cohort study of 2175 episodes during the years 1999–2001 and 2005–2010

Abstract

Background: Nosocomial infections are major causes of morbidity in hospitalized patients. Methods: Retrospective laboratory-based surveillance during 1999–2001 and 2005–2010 identified 2175 cases of nosocomial bloodstream infections (BSIs) in Tampere University Hospital (TAUH), Finland. Results: Analysis revealed that 57% of BSIs were caused by a gram-positive organism, 27% by a gram-negative organism, 5% by a fungal organism, and 11% were polymicrobial. The most common cause of nosocomial BSI was coagulase-negative staphylococci (23%). Candida species caused 5% of the infections. The 7-day and 30-day case fatalities were 8% (161/2158) and 15% (313/2175), respectively, and were highest in BSIs caused by Candida albicans (22% and 44%) and Pseudomonas aeruginosa (17% and 25%). The median age of patients was 54 years in 1999–2001, 57 years in 2005–2007, and 60 years in 2008–2010 (p < 0.001). The median time from hospital admission to the onset of BSI was 11 days (quartiles 5–18 days). This period was shortest for Streptococcus agalactiae BSI and longest for Candida non-albicans fungemia (1 vs 19 days). The case fatality rate in nosocomial BSI decreased during the years studied: 7-day and 30-day case fatalities were 9% and 16% during 1999–2001, 8.5% and 16% during 2005–2007, and 5% and 12% during 2008–2010, respectively (p < 0.003 and p = 0.022, respectively). Conclusions: Gram-positive infections predominate in nosocomial BSIs. The median age of patients with nosocomial BSI has risen during the study years. The case fatality associated with nosocomial BSI has decreased.

Keywords::

• BSI
• nosocomial
• case fatality
• health-care associated
• incidence

Acknowledgments

We acknowledge the valuable help of hygiene control nurses Jaana Sinkkonen and Erja Mattila who also collected the nosocomial BSI data in TAUH. This work was financially supported by the competitive Research Fund of Pirkanmaa Hospital District.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.