Polymerase chain reaction for early identification of bacteria causing pneumonia in ventilated surgical and trauma patients.

INTRODUCTION

Ventilator-associated pneumonia occurs in 20% to 25% of intubated trauma patients, and early effective antibiotic treatment decreases morbidity and mortality. We sought to determine the sensitivity and specificity of multiplex polymerase chain reaction amplification of bacterial DNA (Biofire FilmArray Pneumonia Panel [BFPP]) obtained during fiberoptic bronchoscopy in predicting the causative bacteria the day of bronchoalveolar lavage (BAL).

METHODS

This diagnostic accuracy study compared results of BAL with quantitative culture and BFPP testing on all intubated trauma and surgery patients suspected of developing pneumonia. Demographics, clinical data, BAL culture results, and BFPP results were recorded. McNemar analysis was performed.

RESULTS

Over a 3-year study period, 151 intubated surgical critical care patients suspected of developing pneumonia underwent 238 BALs with quantitative culture and BFPP testing. Bronchoalveolar lavages that had ≥10 5 colony-forming units/mL growth were considered consistent with the diagnosis of pneumonia. Of the 238 BALs, 82 (34.5%) were considered positive and then correlated to the genomic copy number per milliliter (GCN/mL) reported by BFPP testing.

CONCLUSION

In ventilated patients with high clinical suspicion for pneumonia, a BFPP cutoff value of 10 6 GCN/mL is a sensitive and specific test for initiating antibiotics targeted to the identified organism(s). In addition, a negative BFPP result may limit unnecessary and potentially harmful empiric antibiotic coverage, as its negative predictive value is 99.8%.

LEVEL OF EVIDENCE: Diagnostic Tests/Criteria; Level III.