title: Molecular diversity of CTX prophage in Vibrio cholerae.
abstract: OBJECTIVE
  The objective of this study was to investigate the molecular diversity of CTX genetic element within toxigenic Vibrio cholerae genomes and to determine the genetic diversity of V. cholerae population collected in a 6-year period (2004-2009) in Iran.
  
  
  RESULTS
  The results of mismatch amplification mutation assay (MAMA)-PCR and sequencing showed cytosine nucleotide in positions 203 and 115 in all 50 El Tor V. cholerae strains, which is the same as classical ctxB sequence. One strain yielded amplicons with both El Tor and classical biotype primers in MAMA-PCR indicative of presence of two copies of CTX phages with different genotypes (rstR(ET) ctxB(class) and rstR(ET) ctxB(ET)) integrated within the genome of this isolate, which suggested the integration of two different CTX phages at different occasions or point mutation in one copy of CTX. Sequencing and PCR analysis indicated the presence of hybrid CTX genotype (rstR(ET) ctx(class)) in 70.6% of the isolates; however, only El Tor RS1 phage has been integrated in flanking to the CTX phages with different genotypes.
  
  
  CONCLUSIONS
  Enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) and ribosomal gene spacer-PCR (RS-PCR) showed a relatively homogenous population in different years. Our findings indicate that sequence analysis of RS and ctxB regions has more discriminative power than restriction-based methods.
  
  
  CONCLUSIONS
  Investigating the molecular diversity of CTX prophage among V. cholerae strains helps to establish a new valuable database of genetic information about isolates, which is of great importance for epidemiologic studies in Iran and other countries encountering cholera epidemics.
authors.affiliation: Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: N H
authors.initials: NH
authors.lastname: Aliabad
authors.forename: B
authors.initials: B
authors.lastname: Bakhshi
authors.forename: M R
authors.initials: MR
authors.lastname: Pourshafie
authors.forename: A
authors.initials: A
authors.lastname: Sharifnia
authors.forename: M
authors.initials: M
authors.lastname: Ghorbani
mesh_terms: D001435:Bacteriophages / Q000235:genetics*; D002772:Cholera Toxin / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D005243:Feces / Q000821:virology; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007492:Iran; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D039002:Prophages / Q000235:genetics*; D017422:Sequence Analysis, DNA; D012703:Serotyping; D041241:Vibrio cholerae O1 / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D002772:Cholera Toxin