The Clinical Significance of FilmArray Respiratory Panel in Diagnosing Community-Acquired Pneumonia

Chen, Huanzhu; Weng, Huilan; Lin, Meirui; He, Ping; Li, Yazhen; Xie, Qingdong; Ke, Changwen; Jiao, Xiaoyang

Microorganism measurement is an integral part of CAP patient management. Accurate and rapid etiological diagnosis helps prevent secondary infection, prevent the use of unnecessary antibiotics, facilitate more timely use of antiviral drugs, and shorten hospital stays [13] . In our study, even with bacterial (or fungal) culture, antibody IgM detection, multiple PCR, and FilmArray RP, there were 18/74 cases (24.32%) of CAP that could not find the pathogens. The multiplex real-time PCR can detect a broad spectrum of respiratory microorganisms promptly, which makes it possible for clinician to treat the patients with specific antimicrobial agents. However, the main limitations of PCR method include the handling of whole batch samples (at least 8 samples) for cost and labor saving, the different boxes to do extraction, the training of specialized biologist that may be the main reason of DNA/RNA extraction and amplification being easily contaminated, and results interpretation (the frequency of false positive or false negative results hinders the use of PCR in clinical practice). Thus, the PCR is not appropriate for instant point of care especially to some severe patients. Compared with multiple PCR, the measurement time of FilmArray RP needs only about 1.2 hours and there is no need to do the experiment in batch. The single test set makes it meet the requirement of clinician to decide whether the patients should be quarantined or not. For some virus, such as Flu A, rapid diagnosis may help prevent secondary OC43 + HRV RSV + HRV HRV spread, beneficial for preventing virus nosocomial transmission. In children and adults, neuraminidase inhibitors reduce median time to resolution of symptoms by 0.5-2.5 days when administered within 48 h of onset of symptoms [14] . Early use of neuraminidase inhibitors reduces the development of complications such as pneumonia [15] . From these points, the FilmArray RP offers potential advantage in patient's treatment. Due to undeveloped immune system, mixed infections with two or more respiratory viruses are common in children but are not easily detected by conventional methods; hence, the biological significance of dual infections currently is not well understood [16] . It will have more clinical significance to analyze the association between age and pathogens. In our study, FilmArray RP had higher sensitivity in detecting the dual viral infection than multiple PCR. Similarly, from previous study, RSV is the predominant virus inducing severe pneumonia in the population [17] [18] [19] and is found to be the most common cause of severe respiratory disease in infants [20] . RSA and Flu A continue to be the major causative agent in dual viral infection. In this study, the detection rate of rhinoviruses was higher than for other respiratory viruses, though its role in pneumonia is still questioned [21] . The prevalence of adenovirus-associated CAP is fairly low (3/74, 4.1%), which is similar to the previous study, but this type of infection is important to recognize because it might induce severe and fatal necrotizing pneumonia (especially serotypes 3, 7, and 14) [22] . For this, PCR is substantially more sensitive for identification of adenovirus than antigen detection [23] . Due to the wide range of pathogens responsible for CAP, in moderate or severe infection, broad-spectrum antimicrobial cover should be initiated before deescalating to narrow spectrum pathogen-directed agents once a microbiological diagnosis ha