How to detect Clostridium difficile variant strains in a routine laboratory

Clin Microbiol Infect. 2001 Aug;7(8):417-20. doi: 10.1046/j.1198-743x.2001.00290.x.


Toxin A-negative, toxin B-positive strains (A-/B+) are the best studied examples of Clostridium difficile variant strains. In addition, there are some other groups of variant C. difficile strains that produce both toxins (A+/B+) or are non-cytotoxic (A-/B-) but differ from the reference strain VPI 10463 in their toxin genes. Here we describe two simple methods (amplification of the tcdA gene and amplification of the binary toxin gene cdtA) which can be used in rapid screening for variant C. difficile strains in collections or in routine laboratories.

Publication types

  • Review

MeSH terms

  • Bacterial Proteins*
  • Bacterial Toxins / analysis
  • Bacterial Toxins / biosynthesis
  • Clostridium difficile / classification*
  • Clostridium difficile / genetics
  • Clostridium difficile / metabolism
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • Enterocolitis, Pseudomembranous / diagnosis
  • Enterocolitis, Pseudomembranous / microbiology*
  • Enterotoxins / analysis
  • Enterotoxins / biosynthesis
  • Humans
  • Polymerase Chain Reaction / methods


  • Bacterial Proteins
  • Bacterial Toxins
  • DNA, Bacterial
  • Enterotoxins
  • tcdA protein, Clostridium difficile
  • toxB protein, Clostridium difficile