title: Molecular Genotyping of Shigella sonnei Strains Isolated From Children With Bloody Diarrhea Using Pulsed Field Gel Electrophoresis on the Total Genome and PCR-RFLP of IpaH and IpaBCD Genes.
abstract: BACKGROUND
  Identification, understanding of antibiotic sensitivity patterns and molecular characterization of genetic elements of Shigella species are important because of both epidemiological and clinical indications in developing countries.
  
  
  OBJECTIVE
  The aim of this study was to analyze molecular epidemiology of Shigella isolates recovered from children with diarrhea in Shiraz (Southern Iran), using IpaH and IpaBCD PCR-restriction fragment length polymorphism (RFLP), and to determine pulsed field gel electrophoresis (PFGE) patterns of total DNA of the S. sonnei isolates to find the clonality among these strains.
  
  
  METHODS
  A total of 82 clinical strains of Shigella spp., S. sonnei (n = 61), S. flexneri (n = 16), Shigella boydii (n = 3) and S. dysenteriae (n = 2) isolated from the stool samples of 719 patients, aged two months to 14 years, with positive occult blood (OB) test were characterized based on their IpaH and IpaBCD genes PCR-RFLP patterns. Genomic DNAs of S. sonnei strains were analyzed by PFGE.
  
  
  RESULTS
  All Shigella isolates were positive for both invasive genes and showed homogeneous profiles for such genes except for two S. sonnei strains, which had IpaH bands with different sizes and PCR-RFLP profiles. Forty palsotypes were determined among the 41 S. sonnei strains. Sample patterns were divided into two groups based on the drawn dendrogram with a similarity range of 70% to 100%.
  
  
  CONCLUSIONS
  The results revealed that the strains under study could be epidemically related. It seems that an alternative subtyping method is needed to study the relationship among clinical S. sonnei strains and their transmission. Here, we reported for the first time, two strains of S. sonnei with a different PCR-RFLP pattern for IpaH gene.
authors: Professor Alborzi Clinical Microbiology Research Center, Nemazi Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
authors: Shohreh
authors: S
authors: Farshad
authors: Molecular Biology Research Center, Baqiyatallah University of Medical Sciences, Tehran, IR Iran.
authors: Reza
authors: R
authors: Ranjbar
authors: Professor Alborzi Clinical Microbiology Research Center, Nemazi Hospital, Shiraz University of Medical Sciences, Shiraz, IR Iran.
authors: Marziyeh
authors: M
authors: Hosseini
keywords: Restriction Fragment Length Polymorphism; Shigella sonnei