Medicine

TB in the Hot Zone

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Science  15 Oct 2004:
Vol. 306, Issue 5695, pp. 375
DOI: 10.1126/science.306.5695.375d

A worrying characteristic of tuberculosis (TB) nowadays is its ability to generate “hot zones” of multi-drug-resistant strains of Mycobacterium tuberculosis. Blower and Chou have developed an amplifier model by which they can track the emergence and evolution of strains into hot zones that have serially accumulated resistance to several drugs, and they have verified their model with World Health Organization data. Paradoxically, it seems that high-intensity control measures, which have most successfully reduced the incidence of sensitive strains, may have promoted the emergence of hot zones, even when the resistant strains are less fit and less transmissible. This is because if strains of bacteria escape cure, the victims of such resistant TB stay infectious for longer and the bacteria may thus go on to accumulate more modes of resistance. Nevertheless, there is time to act: The model also indicates that even after 30 years of poor drug control, only low levels of multi-drug resistance emerge. Regionally customized control programs could thus be developed to deal with local varieties and combinations of drug-resistant strains. — CA

Nature Med. 10, 1111 (2004).

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