Gene Xpert MTB/RIF Assay as A New Tool for Tuberculosis Diagnosis and Detection of Rifampin Resistance

Abstract

Background: Mycobacterium tuberculosis (MTB) is one of the top ten causes of death and the leading cause of a single infectious agent (above HIV/AIDS) Worldwide. Each year millions of people continue to fall sick with TB. Aim: To evaluate the MTB/RIF assay for rapid diagnosis and detection of rifampin resistance of tuberculosis in both positive and negative smears-as well as pulmonary and non-pulmonary clinical specimens. Patients and Methods: A prospective study was conducted on 50 patients (37 pulmonary, 13 extrapulmonary) patients attending the Outpatient Clinic and inpatients of Chest Department, Benha University Hospital, Egypt. Pulmonary samples were analyzed by (Sputum smear exam. by Ziehl Neelsen (ZN) stain, culture on Lowenstein-Jensen(LJ)media, and assessment of rifampin sensitivity). Extrapulmonary samples were analyzed by reference methods (pathological diagnosis) and by GeneXpert. Results: pulmonary patients’ smears were 32 (86.5%) positive and 5 (13.5%) negative. Culture on LJrevealed rifampin sensitivity in 33/37 (89.1%) and rifampin-resistant in 4/37 (10.9%), GeneXpert was positive in 32(86.5%) and negative in 5 (13.5%), rifampin assay was sensitive in 33 (89.1%) and resistant in 4(10.9%). All extrapulmonary patients, (n=13) were positive on GeneXpert and sensitive for rifampin. Conclusion: GeneXpert could be considered as a leading way to early diagnosis, treatment, and prevention of transmission of tuberculosis which could reduce TB- associated morbidity and mortality.