Biological microchips for detection of multiple drug resistant M. tuberculosis strains isolated in Kyrgyz Republic

Abstract

The aim of the study was to estimate spread of primary and secondary multiple drug resistant Mycobacterium tuberculosis (MBT) and to characterize rpoB, katG, inhA, and ahpC gene mutations of rifampicin (RIF) and isoniazid (INH) resistant MBT strains isolated from tuberculosis patients in Kyrgyz. We obtained 493 specimens from patients with pulmonary tuberculosis which were diagnosed based on clinical, X-ray, and bacteriological examination. Among them, newly diagnosed pulmonary tuberculosis was in 445 patients (90.2 %), and 48 of the patients (9.8 %) have already been treated for tuberculosis. Mutations of rpoB, KatG, inhA, and ahpC genes associated with RIF and INH resistance were detected by biological chip test. Sensitive MBT strains were detected in 47 % and resistant strains were in 53 % of the newly diagnosed patients. Single-drug resistance to RIF only was detected in 3 % of cases; resistance to INH was found in 20 %, resistance to both the drugs was detected in 30 % of the patients. In pre-treated patients single-drug resistance to RIF was defined in 4 % of cases, resistance to INH was in 8 %, resistance to both the drugs was estimated in 75 % of the patients. Therefore, we suppose that there is a high prevalence of multi-drug resistant MBT in Kyrgyz Republic: 30 % among newly diagnosed patients and 75 % among pre-treated patients. The main cause of RIF-resistance of MBT is Ser531→Leu mutation of rpoB gene, and the main cause of INHresistance is Ser315→Thr mutation of katG gene.