title: Instability of IS6110 patterns in multidrug-resistant strains of Mycobacterium tuberculosis.
abstract: The stability of IS6110 restriction fragment length polymorphism (RFLP) pattern was determined in 31 isolates from patients with multidrug-resistant tuberculosis (MDR-TB). These patients were in actual chains of transmission and they referred to the National Institute of Tuberculosis and Lung Diseases, Tehran, Iran. Susceptibility testing against first- and second-line drugs were performed by the proportional method on Lowenstein-Jensen culture media. Thereafter, DNA fingerprinting by IS6110 with direct repeat (DR) region as a probe was performed by standard protocols. The rate of IS6110 changes was 16%, although, no variation was found in the DR region, in a time-span of 1-63 months. The strains with unstable IS6110 patterns were resistant to all drugs tested, and the majority of them (60%) were collected from HIV-positive patients. The results demonstrated that for a reliable interpretation of strain typing, it is better to use an additional marker along with IS6110 RFLP.
authors.affiliation: National Research Institute of Tuberculosis and Lung Disease, WHO Collaborating Centre of Tuberculosis, Darabad, Tehran, Iran. pfarnia@hotmail.com
authors.forename: P
authors.initials: P
authors.lastname: Farnia
authors.forename: M R
authors.initials: MR
authors.lastname: Masjedi
authors.forename: B
authors.initials: B
authors.lastname: Nasiri
authors.forename: M
authors.initials: M
authors.lastname: Mirsaedi
authors.forename: S
authors.initials: S
authors.lastname: Sorooch
authors.forename: M
authors.initials: M
authors.lastname: Kazeampour
authors.forename: A A
authors.initials: AA
authors.lastname: Velayati
mesh_terms: D000328:Adult; D000995:Antitubercular Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D016172:DNA Fingerprinting; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D012150:Polymorphism, Restriction Fragment Length; D018088:Tuberculosis, Multidrug-Resistant / Q000188:drug therapy / Q000453:epidemiology / Q000235:genetics*
chemical_list: D000995:Antitubercular Agents