Research

The Beijing genotype and drug resistant tuberculosis in the Aral Sea region of Central Asia

Helen Suzanne Cox¹ , Tanja Kubica² , Daribay Doshetov³ , Yared Kebede⁴ , Sabine Rüsch-Gerdess² and Stefan Niemann²

¹  Médecins Sans Frontières (MSF), Aral Sea Area Programme, Uzbekistan and Turkmenistan Tashkent, Uzbekistan

²  National Reference Center for Mycobacteria, Forschungszentrum Borstel, Borstel, Germany

³  Ministry of Health, Nukus, Karakalpakstan, Uzbekistan

⁴  Médecins Sans Frontières (MSF), Amsterdam, Holland

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Respiratory Research 2005, 6:134doi:10.1186/1465-9921-6-134

Published:	8 November 2005

Abstract

Background

After the collapse of the Soviet Union, dramatically increasing rates of tuberculosis and multidrug-resistant tuberculosis (MDR-TB) have been reported from several countries. This development has been mainly attributed to the widespread breakdown of TB control systems and declining socio-economic status. However, recent studies have raised concern that the Beijing genotype of Mycobacterium tuberculosis might be contributing to the epidemic through its widespread presence and potentially enhanced ability to acquire resistance.

Methods

A total of 397 M. tuberculosis strains from a cross sectional survey performed in the Aral Sea region in Uzbekistan and Turkmenistan have been analysed by drug susceptibility testing, IS6110 fingerprinting, and spoligotyping.

Results

Fifteen isolates showed mixed banding patterns indicating simultaneous infection with 2 strains. Among the remaining 382 strains, 152 (40%) were grouped in 42 clusters with identical fingerprint and spoligotype patterns. Overall, 50% of all isolates were Beijing genotype, with 55% of these strains appearing in clusters compared to 25% of non-Beijing strains. The percentage of Beijing strains increased with increasing drug resistance among both new and previously treated patients; 38% of fully-susceptible isolates were Beijing genotype, while 75% of MDR-TB strains were of the Beijing type.

Conclusion

The Beijing genotype is a major cause of tuberculosis in this region, it is strongly associated with drug resistance, independent of previous tuberculosis treatment and may be strongly contributing to the transmission of MDR-TB. Further investigation around the consequences of Beijing genotype infection for both tuberculosis transmission and outcomes of standard short course chemotherapy are urgently needed.