LightCycler SeptiFast in early diagnosis of sepsis: our experience

Introduction

The conventional sepsis diagnosis, using the cultivation technique, needs 24 hours for bacterial identification and 36 hours for fungal. The use of empiric therapy makes the growth of bacteria and fungi slower or may yield negative findings in many cases of septic shock. The molecular technique can contribute to a more rapid and specific diagnosis in septic patients. SeptiFast detects 26 bacterial and fungal species DNAs, using the PCR in real time and giving results after 6 hours. This is important for de-escalation therapy and beginning of appropriate antibiotic treatment. The aim of this study is to evaluate the sensibility and the specificity of the SeptiFast test versus traditional diagnosis.

METHODS

We enrolled 16 patients admitted to the ICU in the past 6 months with surgical severe sepsis and septic shock. All patients were treated with empiric antibiotics at the time of testing. Fungal and bacterial DNA was detected by the LightCycler SeptiFast. We compared the results of molecular diagnosis with the cultivation technique (BACTEC 9050) and microbiological blood culture

Results

The preliminary results are presented in Table 1.

Table 1 Comparison of results

Conclusion

The results of BACTEC and SeptiFast were the same in 12/16 (75%) patients. In 3/16 (18%) patients the SeptiFast test showed a positive result, not detected by BACTEC. In only 1/16 (6%) we found a positivity in BACTEC, and negativity in SeptiFast. This result was probably due to contamination of samples for BACTEC. SeptiFast is a valuable add-on to the traditional gold standard with cultivation methods, also during antimicrobial treatment. This study represents a limited assessment of the PCR's performance. To properly assess the clinical value of this technique, a prospective study with a larger population could be useful.