Investigation of the Susceptibilities of Mycobacterium Tuberculosis Complex Strains to Major Antituberculosis Drugs with Bactec MGIT 960 System

Abstract

Objective: The study was designed to investigate retrospectively the resistance rates of tuberculosis-causing mycobacteria, isolated in the microbiology and clinical microbiology laboratories of Konya Research and Education Hospital. Material and Method: Mycobacterium tuberculosis complex strains were isolated from various clinical samples of 1666 patients applying to Konya Research and Education Hospital between May 2007 and December 2009, and the resistance rates of Mycobacterium tuberculosis complex strains against first generation anti tuberculosis drugs were investigated. After homogenization and decontamination, the samples investigated were cultured using BACTEC Mycobacteria Growth Indicator Tube-960 (MGIT-960) system. Susceptibility rates of the strains determined with production were investigated with the same system versus streptomycin (SM), Isoniazid (INH), Rifampin (RIF) and Ethambutol (ETB) (SIRE). Results: From 1666 patients prediagnosed with tuberculosis, 70 Mycobacterium tuberculosis complex strains were isolated. While no drug resistance was found in 17 (24%) of them, resistance to one or two drugs was found in 26 (37%) strains (24% to INH, 20% to SM, 6% to ETB and 4% to RIF). While resistance was found to be only against one drugs in 15 of these (21%), two drugs in 11 of these (16%), no resistant strains could be determined against three or four drugs together. Among the patients with resistance, 81% (57/70) displayed primary and 18% (13/70) secondary tuberculosis, and 2 patients were found to display resistance to isoniazid and rifampin together (MDR-TB). Conclosion: It was seen that the findings in the study were consistent with those determined by other studies in our country. Preventing the resistance to antituberculosis drugs is possible by enlightening the distribution rates of drug resistant strains in public, defining appropriate drug regimes and increasing the quality of tuberculosis control programs. Therefore, it is essential that regular and continuous scanning of antituberculosis drugs should be performed.