Instability of IS6110 patterns in multidrug-resistant strains of Mycobacterium tuberculosis.
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.
Farnia
P
P
National Research Institute of Tuberculosis and Lung Disease, WHO Collaborating Centre of Tuberculosis, Darabad, Tehran, Iran. pfarnia@hotmail.com
Masjedi
M R
MR
Nasiri
B
B
Mirsaedi
M
M
Sorooch
S
S
Kazeampour
M
M
Velayati
A A
AA
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*
D000995:Antitubercular Agents