Park-Williams Number 8 Strain of Corynebacterium diphtheriae

Five clones of the Park-Williams number 8 strain of Corynebacterium diphtheriae, previously maintained in separate laboratories, were examined for their colonial and biochemical properties, for the restriction and modification system which operates to obscure their lysogeny, and for their capacity to produce large amounts of toxin under ordinary laboratory conditions. The phenotypes of their phage, P, produced in strain 603 and C7 (P.603 and P.C7) differ both as to stability to storage in the cold and to inactivation by antiphage serum. Evidence for a high degree of stability in the integration of P prophage in the PW8 genome is presented.     

Restriction endonuclease map of corynebacteriophage omega ctox+ isolated from the Park-Williams no. 8 strain of Corynebacterium diphtheriae.

The toxigenic corynebacteriophage omega tox+ was isolated from the hypertoxigenic Park-Williams no. 8 (PW8) strain of Corynebacterium diphtheriae and compared with the toxigenic corynebacteriophage beta tox+. The physical size and host range of both phages were found to be identical. An endonuclease restriction map of omega tox+ was constructed, and the locations of the cohesive ends (cos), phage attachment site (attP), and the diphtheria tox operon were identified. The genome of omega tox+ was found to differ from that of beta tox+ in three regions. In addition, omega tox+ was shown to be integrated into two nontandem corynebacterial phage attachment sites (attB1, attB2) in the PW8 chromosome. The differences in the restriction endonuclease digestion maps of omega tox+ and beta tox+ and the contribution of double lysogeny are discussed in relation to the hypertoxigenicity of the PW8 strain.     

Corynebacterium diphtheriae nontoxigenic strain carrying the gene of diphtheria toxin

Among 828 C. diphtheriae nontoxigenic cultures isolated in different region of Russia in 1994-2002, 114 cultures (13.8%) had the gene of diphtheria toxin (gene tox) and were thus called nontoxigenic tox-carrying (NTTC) strains. All NTTC strains were found to belong to biovar mitis and formed neither normal, nor "defective" diphtheria toxin. The most of NTTC strains (94%) belonged to ribotype "Moskva", not occurring among C. diphtheriae toxigenic strains. The incapacity of NNTC strains of forming diphtheria toxin was caused by mutation: the deletion of one nucleotide which led to the shift of the open reading frame and to the formation of the stop codon. The results of these studies are indicative of the fact that a sufficiently homogeneous and isolated group of C. diphtheriae nontoxigenic strains is spread in Russia. These strains carry the nonexpressing gene of diphtheria toxin and are of no epidemic importance in diphtheria infection.     

Adhesion in Corynebacterium diphtheriae

The study of 8 C. diphtheriae strains of different origin revealed that these strains were capable of inducing the agglutination of trypsinized sheep red blood cells (SRBC). Toxigenic strains gravis isolated from diphtheria patients were more active in their adhesion to SRBC than toxigenic strains gravis isolated from carriers. The latter were, in their turn, more active than nontoxigenic strains mitis. No fimbriae were detected on the cell surface by electron microscopy.     

Adhesion of Corynebacterium diphtheriae

The conditions for the direct hemagglutination test performed to determine the degree of adhesion of C. diphtheriae were defined. For this test sheep red blood cells, trypsin-treated ex tempore, were used. Only newly isolated cultures, subcultured for not more than 2-5 times and stored for not more than 2-7 days or freeze-dried, were employed. The culture to be tested was grown in nutrient agar with 10% of normal horse serum. The test was made in microtitrator round-bottom wells. The mixture of different dilutions of the culture was incubated for 2 hours at 37 degrees C, then left overnight at 4 degrees C. All 147 newly isolated or freeze-dried C. diphtheriae strains under test had different degrees of adhesion. Their adhesive activity was unrelated to their biovar. Toxigenic strains were significantly more active in hemagglutination (53.5 +/- 3.0%) than nontoxigenic ones (23.5 +/- 3.9%). The strains isolated from the nose, irrespective of their biological properties, were more active than those isolated from the pharynx.     

Neuraminidase of Corynebacterium diphtheriae

Neuraminidase activity has been found in a variety of strains of Corynebacterium diphtheriae, both toxinogenic and nontoxinogenic. The enzyme has been shown to be intracellular, possibly associated with the cytoplasmic membrane. Toxinogenic strains of the diphtheria bacillus, grown under conditions unsuitable for maximal toxin production, produce neuraminidase, and the enzyme has been purified from cells of the Park Williams no. 8 strain grown under such conditions. Diphtherial toxin and diphtherial neuraminidase have similar molecular weights and remain associated during column chromatography; immunochemically, and in their electrophoretic behavior, they appear distinct.