The investigation of viral respiratory tract infections in children by multiplex real-time polymerase chain reaction (PCR) and direct immunofluorescence test

Viral respiratory tract infections are the major cause of morbidity and mortality in children worldwide. The aim of this study was to determine the frequency of viral infections in hospitalized children with lower respiratory tract infections by multiplex real-time PCR test and direct immunofluorescence assay (DFA). Nasopharyngeal swab specimens were collected from 158 children 17 years old and under by using flocked swabs (Copan Diagnostics, Italy) between September 2012 and March 2013. Samples were analysed for 13 respiratory viruses by multiplex real-time PCR test (ARVI Screen Real-TM, Sacace, Italy) and for respiratory syncytial virus (RSV), human metapneumovirus (hMPV), adenovirus and parainfluenza virus (PIV) antigen by DFA test (Argene SA, France). Of 158 patients, 114 (72.2%) were found to be positive for at least one virus by multiplex real-time PCR test. Coinfection was observed in 49 (31%) of all patients. Rhinovirus was the most common virus and detected in 44 (27.8%) patiens, followed by RSV (17.7%), adenovirus (17.7%), hMPV (10.1%), PIV 4 (9.4%), PIV 1 (7.5%), human bocavirus (6.3%), human coronavirus (HCoV) OC43/HKU1 (4.4%), PIV 2 (3.1%), PIV 3 (3.1%) and HCoV 229E/NL63 (1.8%). Compared to real-time PCR test, the sensitivity of DFA test for RSV, hMPV, adenovirus and PIV were 85.7%, 75%, 46.4% and 70.4% and the specificity 96.2%, 96.5%, 89.4% and 94.7%, respectively. In conclusion, viral respiratory infections were identified with a high rate of 72.2% in our study group. To reduce unnecessary antibiotic use and to prevent nosocomial virus transmission, multiplex real-time PCR test should be performed in the early diagnosis of viral respiratory tract infections and DFA test could be also used as a rapid assay especially for RSV and hMPV.