Incidence and mortality of Staphylococcus aureus bacteraemia in Iceland

Abstract number: P1996

Asgeirsson H., Gudlaugsson O., Kristinsson K., Heiddal S., Kristjansson M.

Objectives: To determine the incidence, source and mortality of Staphylococcus aureus bacteraemia in Iceland.

Methods: Cases of S. aureus bacteraemia occurring between January 1 1995 and December 31 2008 were identified by clinical microbiological laboratories performing blood cultures in Iceland. Patients 18 years or older with a positive blood culture for S. aureus were included. Recurrent episodes were classified as re-infections if they occurred more than 90 days apart or if the isolates had a different antibiotic susceptibility profile. If recurrences took place within 90 days they were considered a relapse of the original bacteraemia. From December 1 2003 to November 30 2008 clinical data regarding source was collected from patients' charts (307 out of 308 available, 99.7%). National population statistics and dates of death were retrieved from the National Registry.

Results: 692 individuals from 18 institutions had 721 distinct episodes of S. aureus bacteraemia. Mean age at diagnosis was 62.6 years (range 18 to 99) and male to female ratio was 1.43, extending throughout the study period. During 1995 to 2008 age specific incidence of bacteraemia rose from 22.7 to 28.9 per 105 per year (p = 0.016, trend across years) and 30 day case fatality rate decreased from 27.9% to 8.7% (p = 0.001, trend across years). Susceptibility to penicillin increased from 14.3% to 20.7% (p = 0.13, trend across years), with no correlation between penicillin sensitivity and case fatality (p = 0.8). Four cases of methicillin resistant S. aureus bacteraemia were identified (0.6%), all of whom lived. Among 308 episodes in 2003 to 2008, 125 (40.5%) were hospital acquired, 82 (26.6%) health care associated and 101 (32.8%) community acquired. There was no difference in case fatality between groups (p = 0.36). The most common sources of bacteraemia were intravascular catheters (20.2%) and skin infections (13.4%) whereas the focus was unknown in 23.5%. The 30 day case fatality was highest among those with pneumonia (29.6%) and unknown source (22.2%), and lowest for those with skin (2.4%) and intravascular catheter related (8.1%) infections (p = 0.04).

Conclusion: During 1995 to 2008 a significant increase in the incidence of S. aureus bacteraemia in Iceland and a significant reduction in 30 day case fatality were noted. The reason for this change is not clear. The source of bacteraemia could be identified in majority of cases and different foci were associated with a difference in mortality.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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