Molecular characterization of diphtheria toxin repressor (dtxR) genes present in nontoxigenic Corynebacterium diphtheriae strains isolated in the United Kingdom.

ABSTRACT: Nontoxigenic strains of Corynebacterium diphtheriae represent a potential reservoir for the emergence of toxigenic C. diphtheriae strains if they possessed functional diphtheria toxin repressor (dtxR) genes. We studied the predominant strain of nontoxigenic C. diphtheriae circulating in the United Kingdom to see if they possessed dtxR genes and ascertain whether they were functional. A total of 26 nontoxigenic C. diphtheriae strains isolated in the United Kingdom during 1995 and 4 nontoxigenic strains isolated in other countries were analyzed by PCR and direct sequencing to determine the presence and intactness of the dtxR genes. The functionality of the DtxR proteins was assayed by testing for the production of siderophore in medium containing high and low concentrations of iron. PCR ampl

SUBMITTER: De Zoysa A 

PROVIDER: S-EPMC540142 | biostudies-literature | 2005 Jan

REPOSITORIES: biostudies-literature