The Importance of Genetic Diagnosis of Infectious Diseases

Background and aim: conventional methods are difficult to identify for some infectious agents in laboratories. many routine procedures are not responsive in the diagnosis of infectious diseases. diagnosis of these diseases is mainly based on the cultures of clinical specimens that have limitations on the rate of detection and specificity. for example, either the cultures do not grow well, or the growth are time-consuming, overlapping, or have obvious affinities. misdiagnosis of infectious elements can lead to wrong treatment. but today with accurate and faster genetic techniques, we can diagnose them more quickly and accurately that have difficult to diagnose and treat. some pulmonary infectious caused by nocardia spp and mycobacterium spp. clinical symptoms of nocardia spp are similar to the infection caused by mycobacterium tuberculosis. in the direct view, these two species have similarities in appearance, both are acid fast. on the other hand, they cause disease in the same organ and cause misdiagnosis. therefore, we decided to devise a rapid molecular method for better, concurrent and explicit diagnosis to aid in the diagnosis and treatment. the aim of this study was to investigate the synchronous of nocardia and mycobacterium in pulmonary samples in patients with suspected pulmonary tuberculosis using multiplex real-time pcr technique. for these reasons, we designed and developed a multiplex cybr green real time pcr method and implemented it on 150 patients with pulmonary tuberculosis.methods: we obtained 150 sputum specimens from patients who were suspected of having pulmonary tuberculosis samples were investigated by culture and multiplex cybr green real time pcrresults: in this study, from 150 samples, 20 were acid fast positive, 14 positive for mycobacterium tuberculosis by singleplex real time pcr, 10 positive for nocardia asteroids by singleplex real time pcr and 2 positive for mycobacterium tuberculosis and nocardia asteroids by multiplex real time pcr whereas 14 samples were positive for mycobacterium tuberculosis with commercial test.conclusion: separate identification methods for pulmonary tuberculosis will be useful for better and faster treatment of these patients. in the diagnosis of patients with suspected pulmonary tuberculosis, concurrent nocardia examination should also be considered.