The lower respiratory tract infections (LRTI) are a leading cause of hospitalization and death globally [1]. The early initiation of appropriate antibiotics in patients with LRTI is crucial as postponing effective antibiotic administration can adversely affect the prognosis [2,3]. Therefore, diagnostic studies establishing the microbial etiology of LRTI are fundamental to provide effective therapy and administration of appropriate antibiotics to the patients [4,5]. Currently, antimicrobial therapy of LRTI is typically initiated on an empirical basis, because of the traditional diagnostic methods including standard culture and antigen detection assay are not able to detect significant proportion of causative pathogens [6,7]. In addition, standard culture and antibiotic susceptibility tests are time-consuming processes, which require at least 24-48 hours [8]. It is known that delay in antibiotic administration is associated with increased in-hospital mortality, especially in severe infections such as pneumonia [9].