The potential use of spoligotypinga polymerase chain reaction based typing system for differentiation of strains of Mycobacterium tuberculosisfor studying the epidemiology of tuberculosis in developing countries which do not routinely perform mycobacterial culture is described in this issue of Thorax by Heyderman et al in a study from Zimbabwe.¹ How does this newer method compare with the now more established molecular typing methods for tuberculosis?

The most commonly used typing system for tuberculosis is IS6110 based restriction fragment length polymorphism (RFLP).² Extensive experience with IS6110 based RFLP typing has shown that there is a high degree of heterogeneity in typing patterns. This means that the technique is highly discriminatory so that it is unlikely that two organisms will share indistinguishable typing patterns by chance.^3-6 This property has allowed RFLP typing to be used in a variety of ways. For example, typing can be used to confirm outbreaks of . . . [Full text of this article]