title: Multidrug-resistant strains of Mycobacterium tuberculosis isolated from patients in Tehran belong to a genetically distinct cluster.
abstract: Restriction fragment length polymorphism (RFLP) analysis was used to study the molecular epidemiology of tuberculosis (TB) in certain areas of Tehran. 120 isolates of Mycobacterium tuberculosis, including drug-resistant strains (n = 23), were analysed using polymorphic GC-rich sequence (PGRS) and IS6110 probes. There was considerable diversity among the strains cultured from patients from certain areas. The results of RFLP showed that multidrug resistant (MDR) isolates of M. tuberculosis in Tehran belong to a group of strains with low copies of IS6110 and PGRS. The degree of clustering was higher for the drug-resistant strains than for the susceptible ones (65% vs 20%). Based on the demographic data and results of RFLP, it appears that recent transmissions of TB from old patients have occurred in Tehran. However, drug-resistant TB in the city is mainly caused by strains that look different from those cultured from such patients. The majority of MDR isolates (85%) in this study contained a low copy number of IS6110 and PGRS in RFLP, and were mostly recovered from immigrants and refugees.
authors.affiliation: Department of Microbiology, Pasteur Institute of Iran, Tehran. mfeiz@institute.pasteur.ac.ir
authors.forename: M M
authors.initials: MM
authors.lastname: Feizabadi
authors.forename: M
authors.initials: M
authors.lastname: Shahriari
authors.forename: M
authors.initials: M
authors.lastname: Safavi
authors.forename: S
authors.initials: S
authors.lastname: Gharavi
authors.forename: M
authors.initials: M
authors.lastname: Hamid
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D015331:Cohort Studies; D004269:DNA, Bacterial / Q000032:analysis; D003906:Developing Countries; D005260:Female; D006801:Humans; D015994:Incidence; D007492:Iran / Q000453:epidemiology; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000187:drug effects*; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D014505:Urban Population
chemical_list: D000995:Antitubercular Agents; D004269:DNA, Bacterial