Setting: Nine Kazakhstan oblasts, 2001.
Objective: To analyse the genetic relationship of drug-resistant Mycobacterium tuberculosis strains from Kazakhstan and to determine the frequency of the Beijing genotype.
Design: All drug-resistant smear-positive cases identified in nine oblasts during the 2001 nationwide drug resistance survey were analysed by IS6110 fingerprinting and spoligotyping. Isolates were obtained from 150 patients (64 new and 86 retreated cases).
Results: Eight cases (5.3%) of dual infection were identified. Of the remaining 142 strains, 91 (64.1%) were grouped in 18 clusters, indicating a high rate of recent transmission of resistant tuberculosis (TB). This was further confirmed by the origin of the patients as well as by the similar drug resistance patterns of the clustered strains. Accordingly, more than one third of all clustered strains were new cases. About 70% of the resistant strains belonged to the Beijing genotype, compared to only 37.5% in a control group of 40 susceptible isolates.
Conclusions: Transmission of drug-resistant strains seems to contribute to the spread of resistant TB in this high incidence region. The Beijing genotype should be seen as a major cause of drug-resistant TB in Kazakhstan and was found to be associated with drug resistance.