Purpose: Comparing multidrug-resistant M. tuberculosis strains with susceptible strains by molecular epidemiological methods.
Methods: We examined 109 multidrug-resistant strains (MDR-TB) and 226 susceptible strains (S-TB) derived from National Hospital Organization Kinki-chuo Chest Medical Center by restriction fragment length polymorphism (RFLP) with IS6110, and Spacer oligonucleotide typing (Spoligotyping).
Results: In the case of MDR-TB, 47 strains (43.1%) belonged to 12 descriptions of clusters and the number of IS 6110 copies per isolate ranged from 9 to 25. Similarly, 99 strains (43.8%) belonged to 20 descriptions of clusters in S-TB and the distribution of IS 6110 copies were from 1 to 20. On the other hand, 84 strains of MDR-TB (77.1%) and 191 strains of S-TB (84.5%) belonged to Beijing family by Spoligotyping.
Conclusion: MDR and susceptible M. tuberculosis strains were characterized similarities in ratio of clusters by RFLP patterns and high proportion of Beijing family by Spoligotyping. These finding supported the possibility that infectiousness of MDR-TB might be similar to that of S-TB.