Multiplex Polymerase Chain Reaction Versus Standard Bacterial Culture in Critically Ill Children With Suspected Pneumonia.

backgroundBacterial lower respiratory tract infection, particularly ventilator-associated pneumonia (VAP), is a significant cause of morbidity and mortality in children who require mechanical ventilation (MV). Microbiologic diagnosis has relied on bacterial culture, but reverse transcriptase polymerase chain reaction (RT-PCR) with bacterial targets is now available for clinical use. We compared the diagnostic performance of tracheal aspirate (TA) multiplex RT-PCR to culture in children requiring MV with suspected lower respiratory tract infection.

methodsThis is a secondary analysis of a prospective cohort of children (30 days to 18 years) at a single center requiring MV via an endotracheal tube for >72 hours in whom daily research TAs were collected. TAs were collected within 24 hours of clinically obtained cultures and analyzed by RT-PCR using the Biofire FilmArray Pneumonia Panel and compared with clinical culture results.

resultsWe compared the results of culture to RT-PCR for 56 samples at intubation and 74 samples from patients with suspected VAP. RT-PCR demonstrated increased detection of on-panel bacteria compared with culture (intubation 73.2% vs. 55.3% P = 0.048, suspected VAP 68.9% vs. 58.1%, P = 0.17) and had an overall sensitivity of 93.9%, specificity of 43.2% and negative predictive value of 92.1% for detection of pathogenic organisms. Overall, 33.8% of samples were positive by both methods, and 29.2% were negative by both methods. Two samples were positive by both methods but detected different on-panel organisms between culture and RT-PCR.

conclusionsRT-PCR demonstrates high sensitivity and negative predictive value for the detection of on-panel pathogens in respiratory samples from critically ill children requiring MV. RT-PCR use may alter antibiotic prescriptions in this population.