Comparative assays of the rpoB gene for identification of Mycobacterium tuberculosis isolated from patients in Sudan.

OBJECTIVES: To characterise mycobacterial clinical isolates based on amplification of the rpoB gene. SETTING: One hundred and thirty-five mycobacterial isolates cultured from suspected pulmonary tuberculosis (TB) patients were identified phenotypically. Molecular characterisation of the isolates was performed based on amplification of the rpoB gene, using duplex polymerase chain reaction (DPCR), PCR-restriction fragment length polymorphism (RFLP) and nested PCR-based sequence analysis techniques. RESULTS: The DPCR assay identified 129 of 135 (95.5%) clinical isolates as Mycobacterium tuberculosis complex species. Restriction enzyme analysis of the rpoB PCR product using Hind II identified 134 of the 135 (99.3%) isolates as M. tuberculosis complex, while nested PCR sequence analysis of the rpoB gene identified 133/133 examined isolates (100%) as M. tuberculosis species. No mycobacteria other than M. tuberculosis (MOTT) were detected among the studied isolates. CONCLUSION: DPCR, PCR/RFLP Hind II and nested PCR sequence analysis of the rpoB gene techniques showed comparable efficiency in the characterisation of Mycobacterium isolates. Nested PCR sequence analysis of the rpoB gene was superior to PCR/RFLP for characterisation of suspected M. tuberculosis isolates, while the DPCR technique showed less sensitivity. As PCR-RFLP requires less sophisticated laboratory facilities than nested PCR sequence analysis, it would be more appropriate to be adopted for accurate characterisation of mycobacteria in countries with a weak infrastructure.

Detection of Helicobacter pylori glmM gene in bovine milk using Nested polymerase chain reaction.

AIM: The aim was to detect the glmM gene of Helicobacter pylori (H. pylori) in cow's milk from different dairy farms in Khartoum State using Nested polymerase chain reaction (PCR). MATERIALS AND METHODS: A total of 50 milk samples were collected from different dairy farms in Khartoum State (13 from Khartoum, 24 Khartoum North, and 13 from Omdurman Provinces). RESULTS: The generated results showed that 11/50 (22%) were harboring the investigated H. pylori glmM gene in Khartoum State (1/13 [7.7%] Khartoum, 9/24 [37.5%] Khartoum North, and 1/13 [7.7%] Omdurman provinces, respectively). CONCLUSION: To the best of our knowledge, this was the first report on the detection of H. pylori glmM gene in cattle milk in Khartoum State. Nonetheless, the high percentages of H. pylori DNA detection in milk opened new avenues toward exploring the risk of human infection with H. pylori through the consumption of raw milk.