Rapid Identification Viruses from Nasal Pharyngeal Aspirates in Acute Viral Respiratory Infections by RT-PCR and Electrospray Ionization Mass Spectrometry

Chen, Kuan-Fu; Rothman, Richard E.; Ramachandran, Padmini; Blyn, Lawrence; Sampath, Rangarajan; Ecker, David; Valsamakis, Alexandra; Gaydos, Charlotte A.

Diagnosis of the etiologic agent of respiratory viral infection relies traditionally on culture or antigen detection. This pilot was conducted evaluation comparing performance characteristics of the RT-PCR and Electrospray Ionization Mass Spectrometry (RT-PCR/ESI-MS) platform to conventional virological methods for identifying multiple clinically relevant respiratory viruses in nasopharyngeal aspirates. The RT-PCR/ESI-MS respiratory virus surveillance kit was designed to detect respiratory syncytial virus, influenza A and B, parainfluenza types 1-4, adenoviridae types A-F, coronaviridae, human bocavirus, and human metapneumovirus. Patients (N=192) attending an emergency department during the 2007-8 respiratory season consented, and “excess” frozen archived nasopharyngeal aspirates were analysed; 46 were positive by conventional virology and 69 by RT-PCR/ESI-MS, among which there were six samples with multiple viral pathogens detected. The sensitivity and specificity of the assay were 89.1% and 80.3%, respectively. Additional viruses that were not identified by conventional virology assays were detected (4 human bocaviruses and 7 coronaviruses). Samples in which the RT-PCR/ESI-MS results disagreed with conventional virology were sent for analysis by a third method using a commercial RT-PCR-based assay, which can identify viruses not detectable by conventional virologic procedures. Time to first result of RT-PCR/ESI-MS was 8 hours. RT-PCR/ESI-MS demonstrated capacity to detect respiratory viruses identifiable and unidentifiable by conventional methods rapidly.