Molecular and Phenotypic characterization of Mycobacterium tuberculosis resistant to anti tuberculosis drugs

IMPERIALE BELÉN; ZUMÁRRAGA MARTÍN JOSÉ; DI GIULIO A; CATALDI ANGEL; MORCILLO NORA

INTERNATIONAL JOURNAL OF TUBERCULOSIS AND LUNG DISEASE

INT UNION AGAINST TUBERCULOSIS LUNG DISEASE (I U A T L D)

Año: 2013 vol. 17 p. 1088 - 1093

1027-3719

SETTING. North Region of Buenos Aires Province, Argentina. Dr. Cetrángolo Hospital. OBJECTIVES: to characterize drug-resistant (DR), multidrug-resistant and extensively drug-resistant M. tuberculosis isolates identifying its genetics profiles, DR levels and mutations conferring resistance. DESIGN. Conventional drug susceptibility testing and the microplate colorimetric method were used to determine drug-resistance profile and the minimal inhibitory concentration (MIC) to isoniazid (INH), rifampicin (RIF) and levofloxacin (LX) from M. tuberculosis clinical isolates. A multiplex-allele-specific-PCR and DNA sequencing were used to detect mutations in katG, rpoB and gyrA/B genes. Genotyping was performed by spoligotyping and IS6110-RFLP. RESULTS. MIC (µg/mL): INH>32.0, 38.9%; INH: 16.0-2.0, 44.4%; INH<2.0, 16.7%; RIF>64.0, 61.3%; RIF≤8.0, 34.7%. Most LX-R isolates showed MIC: 16.0-4.0. The main mutations found in INH-R isolates were katG315 (53.7%) and inhAP-15 (25.5%). RIF-R isolates showed mutation in rpoB531 (61.9%) followed by rpoB526 (16.7%). Mutations in gyrA94/90 were found in LX-R isolates. Haarlem, LAM and T were the main spoligotyping families found. KatG315 was mainly associated with Haarlem and LAM, while inhAP-15 with T family. CONCLUSIONS. These results showed several aspects about the strains such as those with INH-R mutated in katG and belonging to Haarlem family are prone to become MDR and circulate in the community