Phenotypic and genotypic investigation of multidrug resistance (MDR) as well as extensively drug resistance (XDR) developing towards second-line anti-tuberculosis drugs in mycobacterium tuberculosis complex (MTBC) strains isolated from clinical samples in cukurova region

Occurence of the Extensively Drug-Resistant (XDR) strains by improving resistance also to second-line anti-tuberculosis (anti-TB) drugs of multidrug-resistant (MDR) Mycobacterium tuberculosis complex (MTBC) strains brings about one the of most important human health threats. For this reason, our research aimed to determine the first- and second-line anti-TB drug resistance status of MTBC strains isolated from our region, to use the Multiplex-Real Time PCR assay which determines the mutations for rapid diagnosis of MDR and XDR strains, thus to compare the phenotypic and genotypic results obtained. Clinical samples sent to the CU THAUM and the Regional Laboratory for Tuberculosis were investigated in two different groups consisting of the 44 MDR-MTBC-positive culture specimens and 50 ARB-positive sputum samples. Phenotypically, subsequent to identification of MTBC the first- and second-line anti-TB drug resistance patterns of the isolates were determined by BACTEC MGIT 960 system and Löwenstein Jensen agar proportion susceptibility methods. Wherease genotypically, both existence of MTBC and resistance patterns in terms of MDR and XDR status were simultaneously revealed by multiplex Real-Time PCR assay using the novel Anyplex™ II MTB/MDR/XDR Detection kit (Seegene). As a result of the study, it was observed that results of the phenotypic and genotypic investigations were very consistent, and sensitivity and specifity of the Real-Time PCR assay in MDR detection was 80 % and 100 %, respectively comparing with phenotypic methods. In addition, while XDR cannot detected among MTBC strains, three pre-XDR MTBC strains, two fluoroquinolone-resistant and one injectable drug-resistant, were detected by using both these methods. In conclusion, it was suggested that the new multiplex Real-Time PCR assay is usable and reliable method for detection of MTBK, MDR and XDR. Key Words: Agar proportion susceptibility method, Extensively Drug Resistance (XDR), Multidrug Resistance (MDR), M.tuberculosis complex (MTBC), Real-Time PCR