Author/Editor		Gerič, Barbara
Title		Pogostost, virulenca in opis toksinskega lokusa PaLoc sevov bakterije Clostridium difficile z zapisom za binarni toksin
Translated title		Incidence and virulence of binary toxin gene-positive strains of Clostridium difficile and characterization of their toxin locus PaLoc
Type		monografija
Place		Ljubljana
Publisher		Biotehniška fakulteta
Publication year		2004
Volume		str. 101
Language		slo
Abstract		Clostridium difficile is a causative agent of intestinal infections after antibiotic treatment. Strains of C. difficile can produce three different toxins: TcdA, TcdB and/or CDT. Enterotoxin TcdA and cytotoxin TcdB are believed to be the main virulece factors. Toxin CDT, a clostridial binary toxin, is produced by a smaller number of strains. CDT acts as actin-specific ADP-ribosyltransferase. It is cytotoxic for cultured eukaryotic cells but its role in the development of disease is not well understood. In this work we screened an extensive collection of C. difficile isolates, which do not produce TcdA and TcdB, for the presence of CDT genes. Eight of 58 (14%) of tested isolates had genes for CDT. We showed the production of CDT toxin in three strains and used these' later strains for virulece testing in two different animal models. Antibiotic treated hamsters were susceptibe for infection, but did not develope any sympthoms of disease or showed histological changes in caecum. On the other hand, fluid accumulation in rabbit ileal loop suggests a role of binary toxin in pathogenesis. To determine the prevalence of binarytoxin-posifive isolates in different hosts, we screened 153 human clinical isolates from patiens of one hospital during five years, and 23 isolates mainly from diseased horses and healthy foals. In C. difficile reference strain VPI 10463 , which produces TcdA and TcdB, but no CDT, aproximately 2 kb delection of CDT locus was described. To determine the prevalence of a truncated CDT locus, we screened 93 isolates of different serotypes and toxinotypes. The truncated locus CDT was confirmed in 35 strains, always found in strains with minor changes of locus PaLoc, coding for TcdA and TcdB, compared to reference strain. A full-size CDT locus was found in strains with major changes of PaLoc. (Abstracts truncated at 2000 characters)
Descriptors		CLOSTRIDIUM DIFFICILE VIRULENCE BACTERIAL TOXINS GASTROENTERITIS RABBITS HAMSTERS HORSES BIOLOGICAL ASSAY DISEASE MODELS, ANIMAL POLYMERASE CHAIN REACTION BASE SEQUENCE