[Respiratory Viral Diagnosis by Using an Automated System of Multiplex PCR (FilmArray) Compared to Conventional Methods]

Acute respiratory infections, which are commonly caused by viruses, are an important cause of morbidity and mortality in children. In Argentina, national surveillance programs for the detection of respiratory viruses are usually performed by using immunofluorescence (IF) assays, although it is well known that molecular methods are more sensitive. An automated multiplex PCR device, the FilmArray-Respiratory Panel (FilmArray-RP), can detect 17 viral and 3 bacterial pathogens in a closed system that requires only 5 min of hands-on time and 1h of instrumentation time. A total of 315 respiratory samples from children under 6 years of age suffering from acute respiratory infections, were studied by IF for 8 respiratory viruses and by RT-PCR for rhinoviruses. Later, these samples were tested by the FilmArray-RP. The positivity frequency obtained for the 9 viruses tested was 75% by IF/RT-PCR and 92% by the FilmArray-RP. The positive and negative percent agreement between both methods was 70.5% whereas the negative percent agreement was 99.6% (95% confidence interval:65.5-75.1 and 99.2-99.8 respectively). The FilmArray-RP allowed a higher positive diagnosis (97%) and detected other viruses such as coronavirus NL63, 229E, OC43, HKU1 (10%) and bocavirus (18%). In addition, this method identified multiple coinfections (39%) with 2, 3, 4 and up to 5 different viruses. At present, IF is still the most frequently used method in most Latin American countries for respiratory viruses diagnosis due to its low cost, its capability to process a high number of samples simultaneously and the fast determination of results for the most frequent viruses, which are available within 5h. However, the coming incorporation of molecular methods in routine procedures will significantly increase the diagnostic yield of these infections.