The Study of PncA Gene Using PCR-RFLP and Allele-Specific PCR Methods in Distinguishing Mycobacterium Bovis from Mycobacterium Tuberculosis

Abstract

Background: Bovine tuberculosis is a chronic bacterial disease of cattle that occasionally affects human. A unique mutation at position 169 (C→G) in Mycobacterium bovis differentiates it from Mycobacterium tuberculosis. For the first time, PCR-RFLP method was used in this study to separate the two organisms. Methods: In this study, 98 tuberculosis patients were assessed using microscopic evaluations, culture and antibiogram. Then, nucleotide changes in position 169 were investigated using Allele-specific PCR and PCR-RFLP methods. Finally, the results were compared with spoligotyping results . Findings: Antibiogram revealed 28 subjects (28.57%) to be resistant and 54 (55.1%) to be sensitive to pyrazinamide while and 16 cases (16.23%) showed no growth. Of 28 resistant patients, 3 (3.1%) were diagnosed with M. Bovis using the classical methods. Using molecular methods, 95 (96.93%) out of 98 subjects were diagnosed with M. tuberculosis and 3 (3.06%) with M. bovis. Allele-specific PCR and PCR-RFLP matched with spoligotyping results. Conclusion: Our result showed the incidence of M. bovis infection to be higher in Iranian population (3.1%) than other studied cases (0.5-1%). In addition, we showed that Allele-specific PCR is the method of choice because it is faster and cheaper than PCR-RFLP. However, PCR-RFLP could be a proper alternative to prevent probable mismatches in Allele-specific PCR.

Keywords

• Mycobacterium tuberculosis
• Mycobacterium bovis
• Allele-specific PCR
• PCR-RFLP
• PncA