Transmission dynamics of tuberculosis in a high-incidence country: Prospective analysis by PCR DNA fingerprinting

We have prospectively analyzed the DNA fingerprints of Mycobacterium tuberc ulosis strains from a random sample of patients with newly diagnosed tuberc ulosis in Windhoek, Namibia. Strains from 263 smear-positive patients in wh om tuberculosis was diagnosed during 1 year were evaluated, and the results were correlated with selected epidemiological and clinical data. A total o f 163 different IS6110 fingerprint patterns were observed among the 263 iso lates. Isolates from a high percentage of patients (47%) were found in 29 s eparate clusters, with a cluster defined as isolates with 100% matching pat terns, The largest cluster included isolates from 39 patients. One predomin ant strain of M. tuberculosis caused 15% of cases of smear-positive pulmona ry tuberculosis in Windhoek That strain was also prevalent in the north of the country, suggesting that in contrast to other African countries with is olates with high levels of diversity in their DNA fingerprint patterns, onl y a restricted number of different strains significantly contribute to the tuberculosis problem in Namibia.