Toxin A-negative, toxin B-positive Clostridium difficile

Int J Infect Dis. 2007 Jan;11(1):5-10. doi: 10.1016/j.ijid.2006.04.003. Epub 2006 Jul 20.


Clostridium difficile is a major cause of infectious diarrhea in hospitalized patients. Many pathogenic strains of Clostridium difficile produce two toxins TcdA and TcdB, both of which are pro-inflammatory and enterotoxic in human intestine. Clinically relevant toxin A-negative, toxin B-positive (A(-)B(+)) strains of Clostridium difficile that cause diarrhea and colitis in humans have been isolated with increasing frequency worldwide. This perspective describes these important toxin variant strains and highlights the need to use Clostridium difficile diagnostic methods that can detect both TcdA and TcdB.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Bacterial Proteins / biosynthesis*
  • Bacterial Toxins / biosynthesis*
  • Clostridium difficile / isolation & purification
  • Clostridium difficile / metabolism*
  • Cross Infection / epidemiology
  • Cross Infection / microbiology*
  • Diarrhea / epidemiology
  • Diarrhea / microbiology
  • Drug Resistance
  • Enterotoxins / biosynthesis*
  • Humans


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