According to WHO data, every day about 4 500 people die from tuberculosis (TB) and 30 000 become sick with TB. Over the last decade, the medical community has faced difficulties in fighting tuberculosis due to the emergence of strains that are either extensively resistant to drugs or multidrug resistant.
Currently, Nazarbayev University scientists are conducting studies on tuberculosis, specifically examining how genetic level factors of tuberculosis may influence resistance to basic anti-tuberculosis drugs. After genotyping the clinical isolates to identify M. tuberculosis genetic families, scientists at the Center for Life Sciences, PI ‘National Laboratory Astana’, identified seven main genotypes of tuberculosis strains distributed in Kazakhstan.
W-Beijing family strains are the most commonly distributed kind in Asia and are associated with anti-tuberculosis drug resistance. We identified that this genotype prevails among cases of tuberculosis in Kazakhstan showing up in 60% of new cases and in 83% of recurrent cases. – reported Ulan Kozhamkulov, a leading researcher of the Laboratory of Genomic and Personalized Medicine, PI ‘National Laboratory Astana’.
Beijing family strains spread frequently in Asian countries, although today strains of this family can be found globally and prevail among young people. Strains of Beijing family were first identified during the 1990s in New York (USA) during an outbreak of multidrug-resistant tuberculosis. The strains in this family were named in 1995, when discovery of M. tuberculosis isolates with the same characteristics were found in ‘Beijing’ China, where 92% of all isolates belonged to this family. Among European countries, W-Beijing strains are mostly distributed in Eastern Europe and former USSR countries.
NLA researchers compared the genomes of clinical isolates of M. tuberculosis susceptible to anti-tuberculosis drugs with those of strains that are multidrug resistant and extensively drug-resistant. During the comparative bioinformatics analysis comparing the different strains, they found in the drug-resistant strains four common genetic loci (PE_PPE family genes) that were absent in the susceptible strains. Nazarbayev University scientists assume that these genes contribute to the extension of drug-resistant TB strains and may worsen disease symptoms of TB.
Now the scientists are planning to compare the results on drug-resistant Kazakhstani strains with data available in international databases. This analysis will help in understanding the mechanisms of tuberculosis resistance to anti-TB drugs and contribute to the development of improved tuberculosis diagnostics, vaccines and new anti-tuberculosis drugs.