Prevalence and characterization of a binary toxin (actin-specific ADP-ribosyltransferase) from Clostridium difficile.
In addition to the two large clostridial cytotoxins (TcdA and TcdB), some strains of Clostridium difficile also produce an actin-specific ADP-ribosyltransferase, called binary toxin CDT. We used a PCR method and Southern blotting for the detection of genes encoding the enzymatic (CDTa) and binding (CDTb) components of the binary toxin in 369 strains isolated from patients with suspected C. difficile-associated diarrhea or colitis. Twenty-two strains (a prevalence of 6%) harbored both genes. When binary toxin production was assessed by Western blotting, 19 of the 22 strains reacted with antisera against the iota toxin of C. perfringens (anti-Ia and anti-Ib). Additionally, binary toxin activity, detected by the ADP-ribosyltransferase assay, was present in only 17 of the 22 strains. Subsequently, all 22 binary toxin-positive strains were tested for the production of toxins TcdA and TcdB, toxinotyped, and characterized by serogrouping, PCR ribotyping, arbitrarily primed PCR, and pulsed-field gel electrophoresis. All binary toxin-positive strains also produced TcdB and/or TcdA. However, they had significant changes in the tcdA and tcdB genes and belonged to variant toxinotypes III, IV, V, VII, IX, and XIII. We could differentiate 16 profiles by using typing methods, indicating that most of the binary toxin-positive strains were unrelated.
Gonçalves
Carina
C
UPRES EA2392, Faculté de Médecine, UFR Saint-Antoine, Université Paris 6, France.
Decré
Dominique
D
Barbut
Frédéric
F
Burghoffer
Béatrice
B
Petit
Jean-Claude
JC
D036002:ADP Ribose Transferases / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D016360:Clostridioides difficile / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D003603:Cytotoxins / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004768:Enterotoxins / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D010641:Phenotype
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003603:Cytotoxins; D017931:DNA Primers; D004269:DNA, Bacterial; D004768:Enterotoxins; C041348:tcdA protein, Clostridium difficile; C031815:toxB protein, Clostridium difficile; D036002:ADP Ribose Transferases; C410164:actin-specific ADP-ribosyltransferase, Clostridium