Effectiveness of the lysis centrifugation method isolator 10 system compared to BacT/Alert 3D in detecting bacteraemia

Abstract number: 1733_437

Kharazmi K., Kratzer C., Tucek G., Klimpfinger M., Georgopoulos A.

Objectives: Aim of this study was to compare the effectiveness of the lysis centrifugation method Isolator 10 system to the conventional BacT/Alert 3D system in diagnosis of bacteraemia.

Methods: 300 hospitalised patients with fever of unknown origin were included in the present study. At three different times, especially when patients' blood temperature was rising, one blood sample was taken and divided among the aerobic, the anaerobic BacT/Alert bottle and the Isolator 10 tube.

Results: 129 bacterial and 4 fungal isolates were recovered by using both methods. Isolator 10 System showed a higher detection rate of 31.7% compared to 14% of the BacT/Alert 3D (c2 test p < 0.001). The Isolator 10 system recovered significantly more coagulase-negative staphylococci, viridans streptococci, pneumococci, non-fermenters and fungi, but no obligate anaerobic bacteria were identified. A strong positive correlation (Spearman = 0.76, T-test p < 0.001) between the microbial counts detected by Isolator 10 system and a positive BacT/Alert blood culture was found. All Isolator cultures with a microbial count >12 cfu/mL were also positive using BacT/Alert, whereas microbial counts <5 cfu/mL were not detectable by the conventional blood culture system. Isolator 10 system required 8 to 22 hours to detect staphylococci, Enterobacteriaceae and non-fermenters compared to 21 to 24 hours with BacT Alert. A time range till 48 hours was needed to detect streptococci by using both blood culture systems.

Conclusion: Isolator 10 system showed high effectiveness in detecting pathogens with low microbial counts. Due to high potentiality of contamination and poor recovery of anaerobic bacteria by Isolator 10 system, the combination of both blood culture methods could optimise the diagnosis of bacteraemia.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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