Characterization of multiple and extensively drug resistant Mycobacterium tuberculosis isolates with different ofloxacin-resistance levels

M. tuberculosis Beijing family spoligotypes were identified among 70.8% of isolates with low-level resistance, 84.6% of isolates with high-level resistance and 50% of strains susceptible to all tuberculosis drugs. Fisher's exact test revealed significant difference between Beijing prevalence in groups of drug-susceptible or high-level OFL-resistant M. tuberculosis strains (p-value = 0.032).