TABLE 1.

Strains used in this study

StrainRelevant characteristicsaReference or source
E. coli
    DH5αRoutine cloning and lacZ expressionInvitrogen
    TOP10Cloning PCR productsInvitrogen
C. diphtheriae
    C7(−)Wild type, Mitis biotype, ET?, tox3
    C7(β)hm723dtxR mutant, tox+20
    PW8Biotype?, ET?, tox+, siderophore mutant30
    NCTC13129Strain used for genome sequence (used only for sequence analysis), Gravis biotype, ET8 complex, tox+Sanger Institute
Russian isolates
    1716Gravis biotype, ET8 complex, tox+34
    1718Gravis biotype, ET8 complex, tox+34
    1737Gravis biotype, ET8 complex, tox+34
    1897Gravis biotype, ET8 complex, tox+34
    1751Mitis biotype, ET175, tox+34
    G4193Gravis biotype, ET16, tox34
  • a ET, electrophoretic type; ET is unknown for C7 and PW8, and a biotype for PW8 has not been described. ET8 complex, dominant clonal group associated with the Russian epidemic.