Evaluation of the Binax NOW Streptococcus pneumoniae urinary antigen assay in intensive care patients hospitalized for pneumonia.

OBJECTIVE: To evaluate the diagnostic performance of Binax Now S. pneumoniae urinary antigen rapid immunochromatographic membrane test (ICT) for patients with suspicion of community-acquired pneumonia hospitalized in intensive care and to assess the impact of prior antibiotics on its diagnostic performance. DESIGN AND SETTING: Retrospective study in a medicosurgical ICU in a 700-bed general hospital. PATIENTS: Charts of patients with ICT performed (result blinded) were reviewed between May 2002 and July 2004. ICT has been performed in 140 of the 1,006 patients hospitalized in the unit; two-thirds had received antibiotics prior to admission. MEASUREMENTS AND RESULTS: Diagnosis of pneumonia was made according to usual criteria. All patients had at least one microbiological test. Pneumonia diagnosis confirmed in 108 patients including 32 pneumococcal. ICT was positive in 23 of 32 patients with pneumococcal pneumonia, in 11 of 108 without, and in none of the 32 patients without pneumonia, resulting in sensitivity, specificity, and positive and negative predictive values of, respectively: 72%, 90%, 68% and 92%. Positive likelihood ratios were comparable among patients with or without prior antibiotics (respectively 6 and 12 for 7 in the overall population). CONCLUSIONS: This first clinical evaluation of ICT in intensive care patients hospitalized for suspicion of community-acquired pneumonia, demonstrated performance in accordance with published data even in the case of prior antibiotics. Its clinical interest and impact on antibiotics policy remain to be refined.

Blind and bronchoscopic sampling methods in suspected ventilator-associated pneumonia. A multicentre prospective study.

OBJECTIVE: To compare four sampling methods: blind tracheal aspirate (blind TA), blind protected telescoping catheter (blind PTC), bronchoscopic PTC and bronchoscopic bronchoalveolar lavage (bronchoscopic BAL), for diagnosis of ventilator-associated pneumonia (VAP). DESIGN: Prospective multicentre study. SETTING: Five intensive care units in France. PATIENTS: Sixty-three patients with mechanical ventilation for more than 48 h, no recent antibiotic change (<72 h) and suspected nosocomial pneumonia. INTERVENTIONS: All patients underwent the four sampling methods. Direct examination and quantitative cultures of the four specimens were performed. MEASUREMENTS AND RESULTS: Visible secretions expelled from the catheter were present 40 times (63%) for blind PTC and 45 times (71%) for bronchoscopic PTC. After exclusion of 11 uncertain cases, 34 VAP were diagnosed. Direct examination of PTC (either blind or bronchoscopic) did not differ from direct examination of bronchoscopic BAL in predicting VAP diagnosis and in guiding initial antibiotic treatment correctly. Compared to that of bronchoscopic BAL (0.98), the area under receiver operating characteristics (ROC) curve was smaller for blind TA (0.78, p=0.002), blind PTC (0.83, p=0.009) and bronchoscopic PTC (0.85, p=0.01). When samples with visible secretions expelled from the catheter were considered, blind and bronchoscopic PTC had areas under ROC curve close to that of bronchoscopic BAL (0.90, p=0.22 and 0.91, p=0.27, respectively). CONCLUSIONS: Blind PTC appears to be a good alternative to bronchoscopic sampling for VAP diagnosis, provided that the sample contains visible secretions expelled from the catheter.