Author/Editor		Gerič, Barbara; Johnson, Stuart; Gerding, Dale N; Grabnar, Miklavž; Rupnik, Maja
Title		Frequency of binary toxin genes among Clostridium difficile strains that do not procedure large clostridial toxins
Type		članek
Source		J Clin Microbiol
Vol. and No.		Letnik 41, št. 11
Publication year		2003
Volume		str. 5227-32
Language		eng
Abstract		Pathogenic strains of Clostridium difficile commonly produce two large clostridial toxins (LCTs), A and B, virulence factors responsible for C. difficile disease. Some strains have been reported to produce an additional toxin, a binary toxin designated CDT. Binary toxin has cytotoxic effects on cells in culture, but its role in human disease is not yet defined. In this study we examined the frequency of binary toxin genes (cdtB and cdtA) among C. difficile isolates that do not produce LCTs (A- B-) from a large United States-based collection organized by restriction endonuclease analysis (REA) typing. Of 58 strains tested, 9 (15.5%) were cdtB and cdtA positive, including 4 of 46 (8.7%) non-LCT-producing REA groups, with an estimated prevalence of at least 2% of all non-LCT-producing isolates witbin the collection. Five of the binary toxin-positive strains belonged to toxinotype XI, which does not produce LCTs but has minor parts of the LCT coding region or pathogenicity locus (PaLoc). We describe two new binary toxin-positive variants, one without any remnant of the LCT genes. This previously unknown variation was found in three isolates that were unrelated by REA typing. LCT-negative, binary toxin-positive strains were isolated from symptomatic and asymptomatic patients and from the hospital environment.
Descriptors		CLOSTRIDIUM DIFFICILE BACTERIAL TOXINS DNA RESTRICTION ENZYMES POLYMERASE CHAIN REACTION BACTERIAL TYPING TECHNIQUES