[Microbiological sepsis screening in surgical ICU patients with the "lightCycler" Septifast test--a pilot study]

Abstract

Introduction: An adequate approach to surgically induced sepsis needs an early and targeted antibiotic therapy in addition to focus sanitation. The PCR-based LightCycler Septifast test can detect 90 % of the sepsis-associated microoganisms (e. g., Gram-positive, Gram-negative bacteria, fungi) within only a few hours.

Patients and methods: A systematic microbiological screening was performed using conventional cultures from blood, urine, drain material and tracheal secretions as well as with the culture-independent Septifast test (blood supplemented with EDTA) as a comparison in consecutive surgical patients on the intensive care unit within a defined time period.

Results: Overall, 52 patients were enrolled in the investigation during the study period of 4 months. Out of overall 258 Septifast tests, 33 (12.8 %) were positive. Additional information on the microbial spectrum was achieved in 24 cases (72.2 %) when compared with the simultaneously performed conventional blood cultures; 32 (12.4 %) of 258 blood cultures were positive. If the frequent occurrence of coagulase-negative STAPHYLOCOCCUS (CNS) is classified as contamination, blood cultures resulted 10 times (31.3 %) in additional information compared with the Septifast test including the CNS in 20 cases (62.5 %). Except for Proteus mirabilis, this refers to microorganisms which are not in the analytical spectrum of the Septifast(R) test. A positive Septifast test showed a high coincidence with SIRS (75.8 %).

Conclusion: This first systematic use of the time-saving LightCycler Septifast test shows that it can detect bacteremia in surgical patients at the ICU, with, in part, negative blood cultures. Positive Septifast test results which cannot be explained by clinical symptoms, occur rarely. The detection of pathological microbes with the Septifast test provides additional findings (72.2 %) for therapeutic decision-making, which can be obtained considerably more rapidly in comparison with conventional microbiological cultures (a few hours versus 2 days). For surgical patients with SIRS and subsequent need of intensive care, a Septifast test should be considered. In conclusion, it is recommended that the test should be further and systematically investigated.