title: Heterogeneity of diphtheria toxin gene, tox, and its regulatory element, dtxR, in Corynebacterium diphtheriae strains causing epidemic diphtheria in Russia and Ukraine.
abstract: Diphtheria toxin (tox) and its regulatory element (dtxR) from 72 Corynebacterium diphtheriae strains isolated in Russia and Ukraine before and during the current diphtheria epidemic were studied by PCR-single-strand conformation polymorphism analysis (PCR-SSCP). Twelve sets of primers were constructed (eight for tox and four for dtxR), and three regions within tox and all four regions of dtxR showed significant variations in the number and/or sizes of the amplicons. Two to four different SSCP patterns were identified in each of the variable regions; subsequently, tox and dtxR could be classified into 6 and 12 different types, respectively. The great majority of epidemic strains from both Russia and Ukraine had tox types 3 and 4, and only in a single preepidemic strain isolated in Russia were all eight tox regions identical to those of C. diphtheriae Park-Williams No. 8 (tox type 1). Epidemic strains from Ukraine can easily be identified by dtxR type 5, while the majority of the Russian epidemic strains have dtxR of types 2 and 8. No differences in the tox regions between mitis and gravis biotype strains were observed. However, dtxR types 2, 5, and 8 were identified only in the gravis biotype, and dtxR type 1 was characteristic for the mitis biotype strains. PCR-SSCP is a simple and rapid method for the identification of variable tox and dtxR regions that allows for the clear association of tox and dtxR types with strains of distinct temporal and/or geographic origins.
authors.affiliation: Division of Bacterial and Mycotic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
authors.forename: H
authors.initials: H
authors.lastname: Nakao
authors.forename: J M
authors.initials: JM
authors.lastname: Pruckler
authors.forename: I K
authors.initials: IK
authors.lastname: Mazurova
authors.forename: O V
authors.initials: OV
authors.lastname: Narvskaia
authors.forename: T
authors.initials: T
authors.lastname: Glushkevich
authors.forename: V F
authors.initials: VF
authors.lastname: Marijevski
authors.forename: A N
authors.initials: AN
authors.lastname: Kravetz
authors.forename: B S
authors.initials: BS
authors.lastname: Fields
authors.forename: I K
authors.initials: IK
authors.lastname: Wachsmuth
authors.forename: T
authors.initials: T
authors.lastname: Popovic
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003353:Corynebacterium diphtheriae / Q000235:genetics* / Q000472:pathogenicity; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004165:Diphtheria / Q000453:epidemiology* / Q000382:microbiology*; D004167:Diphtheria Toxin / Q000235:genetics*; D004196:Disease Outbreaks; D005069:Evaluation Studies as Topic; D005798:Genes, Bacterial; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods / Q000706:statistics & numerical data; D018807:Polymorphism, Single-Stranded Conformational; D015203:Reproducibility of Results; D012426:Russia / Q000453:epidemiology; D014455:Ukraine / Q000453:epidemiology
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; D004167:Diphtheria Toxin; C075586:DtxR protein, Corynebacterium diphtheriae