Investigation of Drug Resistant Mycobacterium tuberculosis Strains with Molecular Methods

Öz

The aim of this study was to investigate mutations in the rpoB and embB genes using molecular methods in Mycobacterium tuberculosis isolates phenotypically resistant to rifampicin and/or ethambutol. Drug susceptibility testing of 110 isolates collected in Turkey between 2005 and 2014 was performed using the modified agar proportion method. Molecular analysis was conducted on 28 selected isolates, including 7 rifampicin-resistant strains. Mutations were detected within the Rifampicin Resistance-Determining Region (RRDR) between codons 507–533 of the rpoB gene. The most common mutation was Ser531Leu (TCG→TTG), found in 10 strains; one strain had a His526Asn (CAC→AAC) mutation. These mutations were considered important molecular markers of rifampicin resistance. Rapid molecular detection of these mutations is important for early and effective tuberculosis treatment planning.

Anahtar Kelimeler

• mycobacterium tuberculosis
• drug resistance
• molecular analysis

Moleküler Yöntemlerle İlaç Dirençli Mycobacterium tuberculosis Suşlarının Araştırılması

Öz

Bu çalışmanın amacı, fenotipik olarak rifampisin ve/veya etambutol dirençli Mycobacterium tuberculosis izolatlarında, rpoB ve embB genlerindeki mutasyonları moleküler yöntemlerle araştırmaktır. 2005–2014 yılları arasında Türkiye’den toplanan 110 izolatın ilaç duyarlılıkları modifiye agar proporsiyon yöntemiyle test edilmiştir. Seçilen 28 suşta moleküler analiz yapılmış, 7’si rifampisin dirençli bulunmuştur. rpoB geninde, Rifampisin Direnç Belirleyici Bölge (RRDR) olan 507–533. kodonlar arasında mutasyonlar tespit edilmiştir. En yaygın mutasyon, 10 suşta görülen Ser531Leu (TCG→TTG) mutasyonu, bir suşta ise His526Asn (CAC→AAC) mutasyonudur. Bu mutasyonlar, rifampisin direncinin moleküler göstergeleri olarak önemli bulunmuştur. Moleküler yöntemlerle bu mutasyonların hızlı tespiti, tüberküloz tedavisinin erken planlanması için önemlidir.

Anahtar Kelimeler

• mycobacterium tuberculosis
• drug resistance
• moleküler analiz

Kaynakça

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