Comparison of mycobacterium tuberculosis detection rate depending on the specimen and the test method

Abstract

Introduction. M.tuberculosis laboratory testing results are directly related to the quality and type of the specimen. However, it is considered that the diagnostic test method also is important. Aim. The aim of our work was to estimate the detection of M.tuberculosis rate in the lower respiratory tract and body fluids using a culture on solid media, automated liquid culture system, and molecular detection methods. Materials and methods. The specimens from the lower respiratory tract (sputum (n=76), bronchial secretion aspirate (n=18)) and the sterile body fluids (pleural fluid (n=91), ascitic fluid (n=5), cerebrospinal fluid (CSF) (n=8), pericardial fluid (n=4)) were taken. Every specimen was cultivated on Levenstein-Jensen solid media, in an automated liquid culture system, and were tested using a molecular detection method. The chi-square test and Fisher exact test were used. Results. M.tuberculosis was detected in all bronchial secretion samples, regard less of the method used. In sputum samples, M.tuberculosis was detected more often by automated liquid culture system compared to solid media and molecular detection method (76/76 (100%) vs. 69/76 (90.8%) and 90.8%, respectively, p=0.027). In the pleural fluid samples, M.tuberculosis was found significantly more often when the molecular detection was used compared to liquid culture system and solid media methods (27/91 (29.7%) vs. 9/91 (9.9%) and 8/91 (8.8%), respectively, p<0.001). Similar results were obtained in ascitic fluid samples. M.tuberculosis was found in 4/5 (80%) cases when the molecular test method was used and 0% when other methods were used (p=0.011). Al though in the CSF and pericardial fluid the greater percent age of M.tuberculosis wa [...].