Primary multi-drug resistant Mycobacterium tuberculosis complex isolates among patients with tuberculous lymphadenitis

Tuberculosis has been and continues to be a major health problem in Sudan. Multidrug- resistant tuberculosis [MDR-TB] is a serious problem that affects both treatment and control programs. Study objective: the objective of this study was to detect the mutant genes that are associated with drug resistance to Streptomycin and Rifampicin in M.tuberculosis isolates from Sudanese patients with tuberculous lymphadenitis. Patients & methods: Following informed consent, seventy five patients with lymphadenopathy who were referred to the Lymphadneopathy Clinic at the Institute of Endemic Diseases, University of Khartoum, were enrolled in the study. Fine needle aspiration cytology (FNAC) has been conducted for all patients as routine clinic procedure. Cytomorphologically, thirty cases showed necrotizing granulomatous tuberculous lymphadenitis (30/75; 40 %) while twenty cases (20/75; 26.7 %) showed reactive lymph nodes changes. The remaining twenty five cases had secondary lymph nodes deposits. Aspiration material was subjected to PCR using the IS6110 gene primers to identify M.tuberculosis complex. All cases of tuberculous lymphadenitis group showed similar patterns to H37 Rv with a fragment size of 123 bp while other groups (reactive & malignant nodes) were non-reactive. To detect mutations that are associated with drug-resistance to streptomycin and rifampicin, two set of primers directed towards rpsl 43 and rpoB 531 loci in a PCR-SSCP system were used. For the rpsl 43, twenty seven cases (27/30) showed DNA band patterns identical to H37 Rv (native) while three cases (3/30; 10%) showed different DNA band patterns to H37 Rv, but identical to mutant strain that were associated with drug resistance to streptomycin. For the rpoB, all isolates gave identical patterns to H37 Rv (native)