Molecular detection of respiratory viruses: clinical impact

Viral respiratory tract infections (LRTIs) cause major morbidity in infants and children. Traditionally, respiratory viruses are detected with conventional tests (viral culture and direct immunofluorescence (DIF)), however nowadays viral diagnostics are being revolutionized by the increased implementation of molecular detection methods such as real-time Polymerase Chain Reaction (PCR). We investigated the epidemiology of respiratory viruses in children at the pediatric intensive care unit (PICU) with LRTI. Using real-time PCR we found respiratory viruses in nearly 100% of patients, a two-fold increase in detection compared to the detection rate using conventional viral tests. Furthermore, we showed that real-time PCR can be used reliably to study the quantity of respiratory syncytial virus (RSV) in respiratory samples of patients with RSV LRTI. Subsequently, we evaluated whether real-time PCR impacted antibiotic use. We found that real-time PCR, used in addition to conventional tests, did not lead to a change in antibiotic use in LRTI patients at the PICU. Therefore, there is currently no need to perform real-time PCR routinely at the PICU. This could change for a number of reasons. In the future reliable bacterial PCR assays may become available to exclude bacterial superinfection. Furthermore, real-time PCR may prove valuable to allocate and monitor anti-viral therapy and infection control measures in outbreaks of new pathogenic viruses. Finally, from a scientific point of view, it is important to continue to implement and develop quantitative real-time PCR assays to further elucidate the etiologic role of respiratory viruses.