Evaluation of the geneXpert MTB/RIF assay for early diagnosis of tuberculosis and detection of rifampicin resistance in pulmonary and extrapulmonary specimens

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Purpose: The emerging of multi-drug resistant strains of Mycobacterium tuberculosis complex and the resurgence of tuberculosis have forced new methods for diagnosis and antimicrobial susceptibility to be developed. In this study, we evaluated a recently marketed diagnostic technique, GeneXpert MTB/RIF test, in terms of identifying Mycobacterium tuberculosis complex and detecting rifampicin resistance from clinical samples. Material and Methods: In our study, GeneXpert MTB/RIF assay was compared with conventional and automated culture methods. 389 various clinical samples (171 pulmonary and 218 ekstrapulmonary samples) were cultured with BACTEC MGIT 960 culture system and Löwenstein-Jensen medium and were tested with GeneXpert MTB / RIF test. Results: 23 samples were positive for Mycobacterium tuberculosis complex by GeneXpert MTB/RIF test, but 22 samples were positive for Löwenstein-Jensen medium and BACTEC MGIT 960 culture system. 2 of 23 samples were detected rifampicin resistant at the first study, but re-studying of these samples resulted as rifampicin resistant for only one sample. According to culture findings of all pulmonary samples, the sensitivity and specificity for GeneXpert MTB / RIF test were both 100% (16/16). The sensitivity and specificity for extrapulmonary samples were 83.3% and 99.5%, respectively. Conclusion: GeneXpert MTB / RIF test is an effectual automated molecular diagnostic technique with its successful and reliable performance in early diagnosis of tuberculosis and detecting multi-drug resistant strains.

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Tuberculosis , GeneXpert MTB , RIF , rifampicin resistance

Cukurova Medical Journal

553

Cukurova Medical Journal