title: Molecular Epidemiology of Mycobacterium tuberculosis Isolates in 100 Patients With Tuberculosis Using Pulsed Field Gel Electrophoresis.
abstract: BACKGROUND
  Tuberculosis (TB) is a widespread infectious disease. Today, TB has created a public health crisis in the world. Genotyping of Mycobacterium tuberculosis isolates is useful for surveying the dynamics of TB infection, identifying new outbreaks, and preventing the disease. Different molecular methods for clustering of M. tuberculosis isolates have been used.
  
  
  OBJECTIVE
  During a one year study of genotyping, 100 M. tuberculosis isolates from patients referred to Pasteur Institute of Iran were collected and their genotyping was accomplished using pulsed field gel electrophoresis (PFGE) method.
  
  
  METHODS
  Identification of all M. tuberculosis isolates was accomplished using standard biochemical and species-specific polymerase chain reaction (PCR) methods. Antibiotic susceptibility tests were performed using proportional method. After preparing PFGE plaques for each isolate of M. tuberculosis, XbaI restriction enzyme was applied for genome digestion. Finally, the digested DNA fragments were separated on 1% agarose gel and analyzed with GelCompar II software.
  
  
  RESULTS
  Genotyping of the studied isolates in comparison with the molecular weight marker revealed two common types; pulsotype A with 71 isolates and one multidrug resistant mycobacterium (MDR) case, and pulsotype B including 29 isolates and three MDR cases. No correlation between the antibiotypes and pulsotypes was observed.
  
  
  CONCLUSIONS
  Molecular epidemiology studies of infectious diseases have been useful when bacterial isolates have been clustered in a period of time and in different geographical regions with variable antibiotic resistance patterns. In spite of high geographical differences and different antibiotic resistant patterns, low genetic diversity among the studied TB isolates may refer to the low rate of mutations in XbaI restriction sites in the mycobacterial genome. We also identified three MDR isolates in low-incidence pulsotype B, which could be disseminated and is highly important to consider in TB surveillance programs to prevent the spread of MDR-TB isolates in the population.
authors.affiliation: Department of Sciences, Qom Branch, Islamic Azad University, Qom, IR Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Pooideh
authors.affiliation: Mycobacteriology Department, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Ismail
authors.initials: I
authors.lastname: Jabbarzadeh
authors.affiliation: Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, IR Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Ranjbar
authors.affiliation: Mycobacteriology Department, Pasteur Institute of Iran, Tehran, IR Iran.
authors.forename: Mahnaz
authors.initials: M
authors.lastname: Saifi
keywords: Molecular Epidemiology; Mycobacterium tuberculosis; Pulsed Field Gel Electrophoresis