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Abstract Tuberculosis (TB); infectious disease, which was considered as a challenging global health problems especially in developing countries with greater attention to multidrug-resistant TB (MDR-TB). MDR-TB could be defined as resistance to isoniazid (INH) and rifampicin (RIF), two therapeutic drugs in the first-line TB regimens. (Ahmad and Mokaddas, 2009) Worldwide, about 3.3% of new TB cases and up to 20% of already treated cases have MDR-TB, and in some places as Estonia, and Henan Province, China, the percentage among the new cases increased up to 14 and 11 % respectively. (WHO, 2015) (Dye et al., 2002) The diagnosis of active TB depended on clinical suspicion, chest radiographs, and smears for acid fast bacilli (AFB), then confirmed by solid or liquid culture which still the “gold standard” reference for TB diagnosis. However, this method was time consuming and took several weeks to be completed, so, rapid and accurate methods for detecting MDR-TB isolates was mandatory for better controlling and proper treating the situation from the begging. (Mitchison, 2005) (Sali et al., 2015) (Mani et al., 2014) In recent years, several molecular methods had been developed for detection of mutations in rpo B and kat G genes that caused resistance to INH and RIF, Cepheid Xpert MTB/RIF kit and the line probe assays were considered as examples of these methods which have been commercialized and used in several centers. (Boehme et al., 2010) (WHO, 2008) This molecular method gave the physician the opportunity to detect the resistant bacteria more earlier and enhance the screening and follow up of these groups of patients, from this point of view the objectives of the current work was determined to evaluate the role of GenoType MTBDRplus assay- as one of commercialized molecular methods for MDR-TB- in detecting MDR-TB from sputum of positive TB cases. The present study conducted on Abbasia Chest Hospital, TB Department and included 50 newly discovered positive cases for Mycobacterium Tuberculosis (diagnosed by direct smear), as a cross sectional study, the enrolling subjects fulfilled the inclusive and exclusive criteria of the study; Inclusion criteria: c) Patients with positive sputum smear for acid-fast bacilli. d) Associated clinical and radiological findings suggestive for pulmonary tuberculosis disease. Exclusion criteria: d) Subjects with previous anti-TB failure or relapse. e) Patients with clinical or radiographic findings consistent with other chronic respiratory disease. f) Patients with smear negative even with clinical and radiological finding suggestive TB infection. After all subjects had been giving a written consent prior to participation, the study protocol approved by the Institutional Research and Medical Ethics Committees of Ain-Shams University, then all subjects underwent to the following; 1- Full history taking including; age, sex, smoking status, addiction habits, co- morbidity especially DM, Liver and renal disease, past history of HIV infection or medication used for it and contact with member diagnosed with MDR TB.2- Clinical examination. 3- Chest radiography (X-ray) 4- Routine laboratory investigations including; CBC, Liver function test, Kidney function test and viral serology for HCV, HBV and HIV. 5- Microbiology assessmentof sputum including;Ziehl–Neelsen (ZN) staining and direct microscopy for acid fast bacilli (AFB) The positive sputum sample for acid-fast bacilli subjected to: 4- Sputum culture on Lowenstein-Jensen (L-J) media: (as gold standard test). 5- Drug sensitivity test; (DST) for Rifampicin and INH by using the proportion method (Heifets, 2000). 6- Mutation detection including; d) Genomic DNA isolation of the MTB from sputum samples using QIAGEN QIA amp DNA mini kit. e) Genotype analysis by Real-Time Polymerase Chain Reaction(RT-PCR)strip technology using GenoType MTBDR plus assay (Hain Lifescience, Nehren, Germany) Statistical analysis The data collected, tabulated and statistically analyzed using IBM SPSS statistics (Statistical Package for Social Sciences) (V. 22.0) software version 22.0, IBM Corp., Chicago, USA, 2013. The results summarized in the following points; 1. The mean age of the studied patients was (37.54 ±11.06) years, (70 %) of them were males, (54 %) were smoker, (34 %) were addict to different form of addiction; the majority were oral tablets (16 %), then inhalation (10 %) and finally (8 %) were IV drug addict 2. from the fifty TB patients (22 %) of them gave history of contact with MDR-TB cases, DM recorded in (30 %) of cases as commonest comorbidity presents followed by Liver disease (18 %), renal disease and malignancy (8 and 4 %) respectively. 3. Cough, expectoration and toxic symptoms were the common presentation of patients (98 and 96 %), while haemoptysis presented in (14 %) of patients. 4. The majority of patients presented by unilateral lesion in X-ray (66 %) and (30 %) of patients had bilateral lesion, only 2 cases (4 %) had free chest X-ray. 5. The CBC profile of patients showed; low mean Hb level (9.30 ± 2.13) mg/dL, with normal mean TLC and PLT value (9.76 ± 5.16) *103 cell/uL and (246.60±157.10) *103 cell/uL respectively.Finally ESR elevated than normal values. 6. HCV test was the commonest positive test (14 %) of patients, followed by HIV (10 %) and the least one was HBV (4 %) 7. The prevalence of primary MDR-TB was (12 %) by molecular methods of detection opposite to (8 %) by conventional (culture) methods. 8. The prevalence of mono drug resistance was (28 %) of patients by molecular methods while by conventional way was (30 %). 9. Rifampicin resistance alone detected in (8 %) of patients by molecular methods, while in culture methods was (10 %) 10. INH resistance alone recoded in (20 %) of patients by both molecular and conventional methods 11. The sensitivity, specificity, PPV, NPV and accuracy of the molecular methods in detection of Rifampicin resistance were (100, 97.5, 90, 100 and 98 %) respectively, and in detecting INH resistance were (100, 94.4, 87.5, 100 and 96 %) respectively. 12. Patients characters associated with DR TB infection showed that; Male gender was significantly associated with infection by DR TB, (P = 0.01), with insignificant statistical difference as regarding the age, (P = 0.8). No effect of smoking or addiction habits or any comorbidity on DR development. Positive contact history with MDR patients had significant impact on DR TB infection, (P = 0.008) The patients whom infected with DR TB bacteria were significantly had lower Hb level than the other group, (P = 0.009) Co-infection with HIV, HCV and HBV had insignificant association with DR TB infection, (P = 0.3, 0.4 and 0.5) respectively. |