Diagnosis of Tuberculosis by Conventional and Molecular Methods in Our Laboratory: A 4-Year Assessment

Abstract

Objective: The aim of this study was to compare direct microscopy, culture and Polymerase Chain Reaction (PCR) methods and to present the antibiotic resistance profile of the last 4 years comparatively by conventional and molecular methods.
 Materials and Methods: Bacterial culture, EZN and PCR methods were applied to all samples. Direct rapid resistance test was performed for EZN positive samples. 
 Results: 968 patients were included in the study. Culture was positive in 81 (8%), PCR in 78 (8%) and EZN in 39 (46%) patients. PCR performed on the same day in both respiratory and other samples showed very good agreement with culture, while EZN staining showed moderate agreement. It was observed that the rapid resistance test detected rifampicin resistance which was not detected in culture, and in the case of INH, culture antibiogram and rapid resistance test were fully compatible. Application of the rapid resistance test to every patient with positive EZN staining resulted in very early detection of resistance. 
 Conclusion: It was concluded that PCR tests are useful in the rapid diagnosis of tuberculosis and resistance in suspicious clinical samples.