Marc Leone, Francois Malavieille, Laurent Papazian, Bertrand Meyssignac, Nadim Cassir, Julien Textoris, Francois Antonini, Bernard La Scola, Claude Martin, Bernard Allaouchiche, Sami Hraiech Critical Care 2013, 17:R170 (6 August 2013)
Introduction: In patients with ventilator-associated pneumonia (VAP), administration of an appropriate empirical antimicrobial treatment is associated with improved outcomes, leading to the prescription of broad-spectrum antibiotics including drugs active against methicillin resistant Staphylococcus aureus (MRSA). In order to avoid the overuse of antibiotics, the present study aimed to evaluate the technical characteristics of a rapid diagnostic test (Cepheid Xpert assay) in patients with suspected VAP.
Methods: From June 2011 to June 2012, in patients with suspected VAP, a sample from the bronchial alveolar lavage (BAL) or miniBAL was tested in a point-of-care laboratory for a rapid diagnostic test of methicillin susceptible Staphylococcus aureus (MSSA) and MRSA. The result was then compared to the quantitative culture with a threshold at 104 colony-forming unit per milliliter for bronchoalveolar lavage and 103 colony-forming unit per milliliter for minibronchoalveolar lavage. The study was performed in three intensive care units from two institutions.
Results: 422 samples from 328 patients were analyzed. The culture of six (1.1%) and 28 (6.5%) samples were positive for MRSA and MSSA. The test was not interpretable in 41 (9.3%) cases. The negative predictive values of the rapid detection test were 99.7% [98.1-99.9] and 99.8% [98.7-99.9] for MSSA and MRSA, respectively.
Conclusion: The rapid diagnostic test is reliable to exclude the presence of MSSA and MRSA in the samples of patients with suspected VAP. Its utility should be regarded depending on the prevalence of MRSA.
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