title: Typing Clostridium difficile strains based on tandem repeat sequences.
abstract: BACKGROUND
  Genotyping of epidemic Clostridium difficile strains is necessary to track their emergence and spread. Portability of genotyping data is desirable to facilitate inter-laboratory comparisons and epidemiological studies.
  
  
  RESULTS
  This report presents results from a systematic screen for variation in repetitive DNA in the genome of C. difficile. We describe two tandem repeat loci, designated 'TR6' and 'TR10', which display extensive sequence variation that may be useful for sequence-based strain typing. Based on an investigation of 154 C. difficile isolates comprising 75 ribotypes, tandem repeat sequencing demonstrated excellent concordance with widely used PCR ribotyping and equal discriminatory power. Moreover, tandem repeat sequences enabled the reconstruction of the isolates' largely clonal population structure and evolutionary history.
  
  
  CONCLUSIONS
  We conclude that sequence analysis of the two repetitive loci introduced here may be highly useful for routine typing of C. difficile. Tandem repeat sequence typing resolves phylogenetic diversity to a level equivalent to PCR ribotypes. DNA sequences may be stored in databases accessible over the internet, obviating the need for the exchange of reference strains.
authors.affiliation: Robert Koch Institute, Wernigerode, Germany. zaissn@rki.de
authors.forename: N Henning
authors.initials: NH
authors.lastname: Zaiss
authors.forename: Maja
authors.initials: M
authors.lastname: Rupnik
authors.forename: Ed J
authors.initials: EJ
authors.lastname: Kuijper
authors.forename: Celine
authors.initials: C
authors.lastname: Harmanus
authors.forename: Dolf
authors.initials: D
authors.lastname: Michielsen
authors.forename: Koen
authors.initials: K
authors.lastname: Janssens
authors.forename: Ulrich
authors.initials: U
authors.lastname: Nübel
mesh_terms: D015373:Bacterial Typing Techniques / Q000379:methods*; D016360:Clostridioides difficile / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D004761:Enterocolitis, Pseudomembranous / Q000382:microbiology*; D019143:Evolution, Molecular; D006801:Humans; D010802:Phylogeny; D021521:Ribotyping; D020080:Tandem Repeat Sequences