Rapid identification of Staphylococcus aureus in bronchoalveolar lavage fluid using a DNA probe (Accuprobe).

Abstract

Staphylococcus aureus is one of the prominent causative agents of ventilator-associated pneumonia (VAP). Gram staining of bronchoalveolar lavage (BAL) fluid is not always reliable. A nonisotopid probe (Accuprobe) has been developed by Gen-Probe for the specific identification of S. aureus isolated from cultures. This study was undertaken to assess the reliability of this probe for the early diagnosis of S. aureus VAP. A prospective study in 120 consecutive patients. Department of intensive care medicine at a university hospital. 120 ventilated patients (70 males and 50 females; mean age 52 +/- 12 years; mean simplified acute physiologic score = 13 +/- 4) were studied. 164 bronchoalveolar lavages were performed (none of the patients received prior antibiotic therapy). S. aureus was identified 29 times at significant concentrations (> or = 10(4) cfu/ml) and 7 times at < 10(4) cfu/ml. The sensitivity and specificity of the Accuprobe system were 100 and 96%, respectively. We found agreement between quantitative cultures and probes in 96.3% of cases. We conclude that this probe provides a rapid (< or = 7 h) and accurate diagnosis of S. aureus pulmonary infection.