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Evaluation of the Septifast molecular test applied to bronchoalveolar lavage samples for the microbiological documentation of severe pneumonia in the intensive care unit

Abstract number: P1813

Tankovic J., Baudel J-L., Dahoumane R., Galbois A., Ait-Oufella H., Lemant J., Maury E., Petit J.C., Guidet B., Offenstadt G.

Objectives: An important determinant of outcome in severe community-acquired or nosocomial pneumonia is prompt and appropriate initiation of antimicrobial chemotherapy. To achieve that, rapid and accurate microbiological documentation is of critical importance. We compared the results obtained by microscopic examination and quantitative culture of bronchoalveolar lavage (BAL) samples with those obtained with the rapid molecular test Septifast (SF) applied on those same samples.

Methods: Microscopic examination and culture were performed according to standard protocols. The SF test has been designed for the rapid detection (6 hours) in a 1.5-ml blood sample of the 25 bacteria and fungi representing 90% of the cases of bacteremia. In our study, the protocol for blood was used without modification. Positive results for streptococci, enterococci, CNS and Candida spp. were not taken into account, because these microorganismes were considered as commensals. We determined the sensitivities (SE), specificities (SP), positive and negative predictive values (PPV and NPV) of the three techniques.

Results: 34 consecutive patients with suspicion of infectious pneumonia (19 men, mean age 64±15, immunosuppression 50%, IGS II: 43.5 ±18.3, septic shock 29%, mechanical ventilation 41%) were included between April 10 and July 29 2009. One week after the realization of BAL, all the patient files were reevaluated and the diagnosis of infectious pneumonia was confirmed only for 23 of the 34 patients included (community-acquired: 10; nosocomial: 13). The diagnostic accuracies of the three techniques are shown below. The sensitivity of SF for patients with ongoing antimicrobial treatment was significantly greater than those from the conventional techniques.

Conclusion: For patients with severe pneumonia, analysis of BAL samples with the Septifast® molecular test permits a fastest microbiological documentation than culture and is more sensitive than culture, at least for patients with ongoing antimicrobial treatment at the time of realization of BAL.

 Gram stainCultureSeptifastp
All infected patients (n = 23)
SE0.350.480.74NS
SP0.730.820.55NS
PPV0.730.850.77NS
NPV0.350.430.5NS
Infected patients with ongoing antimicrobial treatment (n = 15)
SE0.140.290.790.02
SP0.670.780.67NS
PPV0.40.670.79NS
NPV0.330.410.67NS

Session Details

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