Evaluation of Clinical Specimens for Extrapulmonary Tuberculosis from Samsun, Turkiye: 2010–2022

Abstract

Tuberculosis is a multisystemic infectious disease that can affect all tissues and organs. Extrapulmonary tuberculosis (EPTB) is defined as the localization of the disease outside the lungs. This study included extrapulmonary samples (EP) sent to the Tuberculosis diagnostic laboratory of Ondokuz Mayıs University Faculty of Medicine between January 2010 and December 2022. In the laboratory, samples were subjected to Ehrlich–Ziehl–Neelsen (EZN) staining, culture on Löwenstein–Jensen (LJ) medium, BACTEC MGIT 960 system (BD, USA), and PCR (2010-2019 GeneXpert MTB/RIF, 2020-2022 BD MAX MDR-TB) for diagnosis. A total of 10 547 extrapulmonary samples were examined in the study. Growth was detected in 185 (1.75%) of the EP samples. Mycobacterium tuberculosis complex was identified in 181 of these samples, while growth of nontuberculous mycobacteria was observed in four samples. Of the samples with growth, 167 (90.27%) were isolated from the adult patient group; 18 (9.73%) were from the pediatric patient group. Looking at the distribution of clinics that sent the samples, it was found that 100 (54%) samples were sent from internal medicine clinics, 67 (36%) from surgical clinics, and 18 (10%) from pediatric clinics. Abscesses accounted for 37 (20%), surgical material 35 (19%), urine 28 (15%), thoracentesis fluid 20 (11%), cerebrospinal fluid 16 (9%), paracentesis fluid 8 (4%), pleural fluid 8 (4%), and others (pericardial fluid, peritoneal fluid, joint fluid, aspiration, exudate, etc.) 33 (18%). EZN positivity in these samples was found to be 18% (33/185). Tuberculosis PCR was applied to 102 (102/185) of these EP samples, and PCR positivity was detected in 79 samples (78%). Of the 79 samples with detected PCR positivity, AFB positivity was also observed in 26 (33%). The detection rate of the M. tuberculosis complex in extrapulmonary specimens has been found to be quite low. Among extrapulmonary specimens, the highest positivity rate was observed in abscess specimens. The use of multiple diagnostic methods (culture + PCR) for detecting M. tuberculosis in extrapulmonary specimens may improve the detection rate.