DETECTION OF LEGIONELLA PNEUMOPHILA IN THE SPUTUM SPECIMENS OF PATIENT WITH RESPIRATORY SYMPTOMS BY CULTURE, PCR AND LOOP-MEDIATED ISOTHERMAL AMPLIFICATION METHODS

Background and Aim:Legionellosis is an important public health problem that can cause substantial mortality and morbidity. This bacterial infection is caused primarily by the Legionella pneumophila found in freshwater environments throughout the world. However, legionellosis risk estimation may be compromised by uncertainties in Legionella detection methods. So the aim of current study was detection of L. pneumophila in patients with respiratory symptoms by culture, polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) methods.Methods:Sputum samples were obtained from patients with respiratory symptoms admitted to the teaching hospitals in Ahvaz, Iran from June 2016 to March 2017. Identification of Legionella spp. was done by culture the sputum directly onto Buffered Charcoal Yeast Extract (BCYE) Agar medium. Then the PCR and LAMP assay were performed to detect the Legionella pneumophila via its Macrophage Infectivity Potentiator (mip) gene in the sputum Specimens.Results:A total of 94 sputum samples were collected. Our results showed that 1 of the sputum samples (1.04%) were culture positive for Legionella spp., 3 (3.12%) and 7 samples (7.28%) of samples were positive for L. pneumophila using the mip gene PCR and LAMP assay, respectively.Conclusion:This study showed that legionellosis should be considered in the diagnosis of respiratory infectious diseases. We also concluded that the LAMP assay is a faster method with high sensitivity and specificity than conventional methods such as PCR and culture for laboratory diagnosis of legionellosis. The LAMP assay can be employed in medical centers with limited equipment without the need of a thermocycling apparatus.DIAGNOSTIC ACCURACY OF MONOCYTE CHEMOTACTIC PROTEIN (MCP)-2 AS BIOMARKER FOR THE DISCRIMINATION BETWEEN ACTIVE AND LATENT TUBERCULOSIS

Keywords:

Legionella pneumophila , Loop-mediated isothermal amplification (LAMP) , mip gene , Sputum