4 research outputs found

    Immunological characterization of diphtheria toxin recovered from Corynebacterium pseudotuberculosis

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    AbstractDiphtheria toxin (DT) is a potent toxin produced by the so-called diphtheria group which includes Corynebacterium diphtheriae (C. diphtheriae), Corynebacterium ulcerans (C. ulcerans), and Corynebacterium pseudotuberculosis (C. pseudotuberculosis). The present investigation is aimed to study in detail the production of DT by C. pseudotuberculosis. Twenty isolates were obtained from sheep diseased with caseous lymphadenitis (CLA) and twenty-six isolates were obtained from 26 buffaloes diseased with oedematous skin disease (OSD). All isolates were identified by standard microbiological and DT production was assayed serologically by modified Elek test and immunoblotting. All sheep isolates were nitrate negative, failed to hydrolyze starch and could not produce DT, while all buffalo isolates (biotype II) revealed positive results and a specific band of 62kDa, specific to DT, was resulted in all concentrated cell fractions (CF), but was absent from non-toxigenic biotype I isolates. At the same time, another band of 31kDa specific to the PLD gene was obtained with all isolates of biotype I and II. Moreover, all isolates showed positive synergistic hemolytic activity and antagonistic hemolysis with β-hemolytic Staphylococci. The obtained results also indicated that C. pseudotuberculosis could be classified into two strains; non-toxigenic biotype I strain, which failed to produce DT as well as being negative to nitrate and starch hydrolysis, and toxigenic biotype II strain, which can reduce nitrate, hydrolyze starch as well as produce DT

    Vaccination against Corynebacterium pseudotuberculosis infections controlling caseous lymphadenitis (CLA) and oedematousskin disease

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    Corynebacterium pseudotuberculosis (C. pseudotuberculosis) is a causative organism of caseous lymphadenitis (CLA) in sheep and acute disease in buffaloes known as oedematous skin disease (OSD). Human affected with the disease show liver abscess and abscess in the internal lymph nodes. The vaccination against CLA up till now occurs by using formalin inactivated whole cells of biovar 1 (sheep strain). Combined vaccine composed of formalin inactivated whole cells of sheep strain and recombinant phospholipase D (rPLD) and another vaccine composed of formalin inactivated whole cells (buffalo origin) and rPLD were prepared in Biotechnology center for services and Researches laboratory at Cairo university and applied for protection against CLA. Both vaccines induced complete protection (100%) against challenge with virulent biovar 1 or biovar 2. Also vaccination against OSD was performed by two types of vaccines. Vaccine-1 was composed of formalin inactivated whole cell biovar 1 combined with rPLD and the second vaccine was composed of formalin inactivated whole cells of biovar 2 combined with rPLD. No lesions developed in vaccinated and non vaccinated buffaloes challenged with C. pseudotuberculosis biovar revealing that biovar 1 C. pseudotuberculosis is not infective for buffaloes. Buffaloes vaccinated with the second vaccine and control non vaccinated animals challenged with biovar 2 (buffalo origin) resulted in development of OSD in all animals. This indicates that OSD results due to production of toxin (s) other than PLD. Discovering this toxin (s) is of value in formulation of a future vaccine against OSD. Keywords: Corynebacterium pseudotuberculosis, Caseous lymphadenitis, Oedematous skin disease, Vaccination, Recombinant phospholipase
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