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Contributions to the taxonomy and biology of Clostridium difficile.

Clostridium difficile was incriminated by Hughes and Jarvis (1987) as a cause of intestinal infections in USA in the 1980-1984 period in 45 p. 100 of cases, whereas Salmonellae only in 12 p. 100. Four strains of this organism are studied in this paper in comparison with ten strains of C. bifermentans and six of C. sordellii, because the three species share a common antigen and have other common characteristics, as well. However, spores of C. difficile swell the bacteria and those of other bacteria (C. bifermentans and C. sordellii) do not; C. difficile does not produce indole, whereas the other species produce it. We confirmed the selective capacity of the medium of George et al. (1979) using the "alcohol shock" and as selective agents cycloserine D and cefoxitin. C. difficile proved to be most susceptible to metronidazole and rifampin. Whereas the former antibiotic was considered as a cause of post-antibiotic intestinal infections by different authors, the second was not, to our knowledge. The strain 10463 has a considerable toxicity (1000 DLM/ml for the white mouse, and pathogenicity--2000--5000 DCL for the white mouse, as compared to 25 DCL of the other three strains). Using this toxin an antitoxic serum was obtained in horse, with a capacity of neutralizing the action of the toxin up to a dilution of 1 p. 1000.

Aerobiosis↗
PubMed1962

Changes in immunodiffusion patterns and in nucleic acid content of Staphylococcus aureus grown in the presence of a nucleic acid fluorochrome.

Sonea, S. (University of Montreal, Montreal, Canada), J. de Repentigny, and A. Frappier. Changes in immunodiffusion patterns and in nucleic acid content of Staphylococcus aureus grown in the presence of a nucleic acid fluorochrome. J. Bacteriol. 84:1056-1060. 1962.-When grown in the presence of acridine orange, coagulase-positive Staphylococcus aureus exhibits changes in the number and the shape of its precipitin bands; these are more pronounced with commercial horse staphylococcal antitoxin than with normal human gamma-globulin. Simultaneously, there is an increase in the content of nucleic acids, especially deoxyribonucleic acid. Consequently, when grown in the presence of this nucleic acid fluorochrome, pathogenic staphylococci become similar to nonpathogenic strains in their antigenic structure and nucleic acid content. The bacterial population becomes a mixture of red and green fluorescing cells of different sizes. After centrifugation, most of the large and red fluorescing cells are found in the top layer, which shows more changes in antigenic composition and in nucleic acid content than the bottom layer. In subcultures grown in the absence of acridine orange, the cells revert to the original composition of the pathogenic strains.

Acridines↗
PubMed1984

[From biotechnology to bacterial toxins and immunomodulators].

The disposal of industrial wastes has been recognized as a serious problem long before the ecological movement gained its present strength. The possibility of using "useful" bacteria for this purpose was considered rather early and numerous studies were made to use them for the biological treatment of industrial wastes. Such attempts have taken advantage of the development of large scale fermentors for the production of bacteria while at the same time they have stimulated progress in the technology of fermentors. The advances made in the technology of fermentors have also made possible the large scale production of pathogenic bacteria. This has made possible the production of bacterial toxins in adequate amounts, enabling investigators to purify them to homogeneity, to characterize the purified toxins physico-chemically and immunologically and to study their structure-function relationships. Similarly, large quantities of bacteria exhibiting specific biological activities could be produced and the constituents responsible for the activities of these bacteria could be isolated and characterized. In this paper, the Author describes the stages of his progress and processes through the fields of the biotechnology and toxinology to that of immunomodulators. His investigations have largely taken advantage of developments in the technology of fermentors. "Ecologic" bacteria have been isolated which are capable of using phenol as the only source of carbon or cyanides as the sole source of carbon and nitrogen. These bacteria have been used for the treatment of industrial wastes enriched either with phenol or with cyanides. Another type of "useful" bacteria investigated was Bifidibacterium bifidus which has a fundamental role in the economy of the breast-fed infant. B. bifidus is present only in the gut of infants fed with mothers-milk. Growth factors for B. bifidus have been isolated from casein hydrolyzates which permitted the implantation of B. bifidus in the gut of infants fed with cows-milk supplemented with these factors. A further development of this type of research has been the large scale production of toxigenic bacteria. As a result large quantities of tetanus toxin have been produced and a method of purification has been devised. The availability of large amounts of purified tetanus toxin made it possible to determine the physico-chemical characteristics of the toxin as well as some of its structure-function relationships. In addition, the mechanism of detoxification of protein toxins by the action of formaldehyde has been clarified. Enzymatically derived toxin fragments have also been purified.(ABSTRACT TRUNCATED AT 400 WORDS)

Adjuvants, Immunologic↗
PubMed1982

Effects of the two toxins of Clostridium difficile in antibiotic-associated cecitis in hamsters.

Hamsters were vaccinated with toxoids containing toxin A, toxin B, both toxins, or a preparation containing neither toxin of Clostridium difficile, the causative agent of antibiotic-associated cecitis in hamsters and pseudomembranous colitis in humans. To determine whether these vaccines would reduce the severity of antibiotic-associated cecitis, the hamsters were injected subcutaneously with clindamycin. Nearly all of the hamsters protected against neither toxin or only one toxin died. These animals developed enlarged hemorrhagic ceca and diarrhea, although the ceca from the animals immunized against toxin B were less hemorrhagic. The hamsters immunized against both toxins survived clindamycin treatment and had ceca of normal size and appearance. Concentrations of both toxins were lower in the ceca of the latter animals than in the unprotected animals. To determine the effects of either toxin alone on the animals, nonimmunized hamsters were injected with either purified toxin A, which produced enlarged ceca with moderate hemorrhaging, or partially purified toxin B, which produced hemorrhagic ceca of normal size. All of the hamsters injected with either toxin at concentrations found in the ceca after clindamycin treatment died. These results suggest that toxin A causes the water influx, that both toxins cause hemorrhaging to different extents in the ceca of hamsters with antibiotic-associated cecitis and that either toxin alone can cause death. These studies may help explain the etiology of pseudomembranous colitis in humans.

Animals↗
PubMed1977

Neutralization of tetanus toxin by human and rabbit immunoglobulin classes and subunits.

This investigation found that the human antibody class of importance in neutralizing tetanus toxin in mice was IgG, and that toxin neutralization was retained by the F(ab')2 and Fab' subunits of the human IgG class. Although human IgM and IgA classes appeared to neutralize tetanus toxin at very low levels, evidence was obtained that this neutralization was probably due to IgG contamination. Human Fabmu isolated from the IgM class did not neutralize tetanus toxin. Human antibodies of the IgG, IgM and IgA classes reacted with tetanus toxoid in the indirect haemagglutination (HA) test with IgG giving the highest HA titre. Rabbit antibodies of the IgG class also neutralized tetanus toxin, with neutralization being retained by the F(ab')2 and Fab' subunits of the rabbit IgG class. Absorption of several rabbit antisera to tetanus toxoid with goat-antirabbit Fc which is specific for absorption of IgG from antiserum, rendered them incapable of neutralizing tetanus toxin.

Animals↗