Mycobacterium tuberculosis in the Al Ain medical district - Epidemiological and DNA evidence for indigenous strains

Oil rich Arabian Gulf countries, including the United Arab Emirates (UAE), have unique population demographics, where expatriate workers represent the majority (> 60% in the UAE). Tuberculosis transmission in these countries is attributed to this influx of foreign labour, especially from neighboring tuberculosis endemic countries, and control measures are aimed largely at eliminating this foreign source. However, this has not resulted in an elimination of transmission. We have used two, IS6110 insertion element based, PCR-DNA analysis systems to identify patterns of transmission among citizen and expatriate patients in the UAE. In PCR system 1, intervening DNA sequences between the PGRS repeat and IS6110 was used. In the second, IS6110 was analyzed with respect to the ipl locus (EMBL X59799). Conventional restriction fragment length polymorphism analysis was also used. Our data show that M. tuberculosis strains isolated from UAE citizen patients were different from those of expatriate workers. We conclude that the primary source of infection in UAE citizen tuberculosis patients is not the expatriate workers, but M. tuberculosis strains indigenous to the region.