Molecular Identification of Mycobacterium Tuberculosis Complex in Formalin-Fixed, Paraffin-Embedded Tissue Blocks of Extra Pulmonary Speciemens using Genomics Extraction

Background: Tuberculosis has been detected in some extra pulmonary ecological niches. Although extra pulmonary tuberculosis (EPTB) is less frequent than Pulmonary Tuberculosis (PTB), its incidence has increased worldwide. The aim of this study was to investigate the presence of EPTB and MDR-EXPT in Formalin-fixed, paraffin-embedded tissue blocks among different samples in Kermanshah, Iran. Methods: Among all the suspected tuberculosis cases referred to the pathology laboratories, 116 patients were included based on the diagnosis of the infectious disease specialist. DNA were extracted from formalin-fixed, paraffin-embedded tissue blocks using genomics extraction G-spin Total DNA Extraction kit and the presence of EPTB was examined by TB Resistant Modual Isoniazid, Rifampicin kit. Results: The frequency of EPTB in the paraffin-embedded block samples was 32% (37 cases), and lymph nodes had the highest frequency (44.5%) followed by Pleural fluid, breast and CSF with the frequencies of 34.6%, 33% and 27% respectively. Conclusions: In the present study we found a high and increasing frequency of EPTB in paraffin- embedded blocks of the participants and it is one of the highest frequencies reported around the world. Since EPTB cases constitute a large number of TB burden, serious attention of public health organizations is recommended.