Identification of a polymorphic nucleotide in oxyR specific for Mycobacterium bovis

Area of Science:

• Microbiology
• Genetics
• Molecular Biology

Background:

• The Mycobacterium tuberculosis complex (MTBC) comprises several genetically similar species, including Mycobacterium tuberculosis and Mycobacterium bovis.
• Accurate differentiation of MTBC members is crucial for epidemiological surveillance and targeted treatment strategies.
• The oxyR gene is involved in the oxidative stress response and has been explored for phylogenetic analysis within MTBC.

Purpose of the Study:

• To identify a specific genetic marker for differentiating Mycobacterium bovis from other members of the Mycobacterium tuberculosis complex.
• To develop a rapid and reliable method for M. bovis identification.

Main Methods:

• Automated sequence analysis of a 410-bp region of the oxyR gene in 105 MTBC isolates.
• Identification of a single nucleotide polymorphism (SNP) at position 285.
• PCR-restriction fragment length polymorphism (PCR-RFLP) analysis using AluI endonuclease on an additional 255 MTBC isolates.

Main Results:

• A unique adenine (A) residue at nucleotide position 285 of the oxyR gene was consistently found in all 29 Mycobacterium bovis isolates.
• All 76 other MTBC isolates analyzed in the initial sequencing study possessed a guanine (G) residue at the same position.
• PCR-RFLP analysis confirmed this A/G polymorphism at position 285 as a reliable marker, distinguishing M. bovis across diverse intercontinental isolates.

Conclusions:

• The nucleotide polymorphism at position 285 in the oxyR gene serves as a highly specific marker for the identification of Mycobacterium bovis.
• This genetic marker facilitates accurate and efficient differentiation of M. bovis within the Mycobacterium tuberculosis complex.
• The findings support the use of this marker in molecular diagnostic and epidemiological studies of bovine tuberculosis and related infections.