Aim: Improvement of etiologic diagnostics of disseminated lung tuberculosis (DLT) and determination of Mycobacterium tuberculosis (MBT) drug susceptibility on the basis of molecular genetic methods.
Materials and methods: Samples from respiratory tract of patients with DLT were studied using real time polymerase chain reaction and the "TB-BIOCHIP" assay developed by Institute of Molecular Biology. Methods of spoligotyping and reverse hybridization were used for identification, genotyping and express-detection of drug resistance of MBT to rifampicin in sputum samples stained for bacterioscopy.
Results: In 76 (41.5%) of 183 patients with radiological signs of DLT, DNA of tuberculosis complex mycobacteria was detected in respiratory tract samples (specificity 87.7%); mutations in genes rpoB, katG, inhA as well as region ahpC-oxyR associated with resistance to rifampicin and isoniazide were revealed in 67% and 79.5% of patients with DLT respectively. In 48.8% of sputum samples, DNA of MBT of epidemically significant genotype Beijing associated with multidrug resistance of MBT in Russia was identified.
Conclusion: Molecular genetic methods allow to use both fresh and archived respiratory tract specimens for rapid verification of DLT diagnosis during oligobacillar forms of tuberculosis as well as timely prescribe and correct the treatment regimen of the patient according to individual drug susceptibility spectrum of the agent.