Immunochromatographic strip test for rapid detection of diphtheria toxin: description and multicenter evaluation in areas of low and high prevalence of diphtheria.

An immunochromatographic strip (ICS) test was developed for the detection of diphtheria toxin by using an equine polyclonal antibody as the capture antibody and colloidal gold-labeled monoclonal antibodies specific for fragment A of the diphtheria toxin molecule as the detection antibody. The ICS test has been fully optimized for the detection of toxin from bacterial cultures; the limit of detection was approximately 0.5 ng of diphtheria toxin per ml within 10 min.

[Identification of Corynebacterium diphtheria biovar belfanti among circulating C. diphtheriae strains in Ukraine].

The biochemical test of the reduction of nitrates to nitrites made it possible to identify 5.2% of strains belonging to biovar belfanti among 135 C. diphtheriae strains, initially classified within biovar mitis.

Evaluation of a single dose of diphtheria-tetanus toxoids among adults in Odessa, Ukraine, 1995: immunogenicity and adverse reactions.

Epidemic diphtheria spread to Ukraine in 1991, where it peaked in 1995 with >5,000 reported cases. To refine epidemic control strategies, immunogenicity of a tetanus-diphtheria toxoids vaccine (Td) containing 2 limits of flocculation (Lf) diphtheria toxoid was evaluated. During a mass vaccination campaign, adults at a clinic in Odessa received one dose of Td.

Molecular epidemiology of diphtheria.

Molecular subtyping of Corynebacterium diphtheriae identified significant genetic diversity within the species and led to the identification of a unique clonal group that emerged in Russia in 1990 at the beginning of the current epidemic. Strains of this group belong to a distinct electrophoretic type complex and are of ribotypes D1 and D4. Identification of the group allowed for precise monitoring of the epidemic's progression and for rapid detection of cases imported to other countries.

Current approaches to the laboratory diagnosis of diphtheria.

Despite the success of mass immunization in many countries, diphtheria continues to play a major role as a potentially lethal resurgent infectious disease. Early, accurate diagnosis is imperative since delay in specific therapy may result in death. The microbiologic diagnosis of the disease, the identification of contacts and carriers, and the appropriate clinical management of these patients are therefore crucial.

A modified Elek test for detection of toxigenic corynebacteria in the diagnostic laboratory.

The detection of toxigenicity among Corynebacterium diphtheriae and Corynebacterium ulcerans strains is the most important test for the microbiological diagnosis of diphtheria. Difficulties with current methods, in particular the Elek test, are well documented. We therefore describe a modified Elek test which provides an accurate result after only 16 h of incubation, in contrast to 48 h for the conventional test.

Analysis of heterogeneity of Corynebacterium diphtheriae toxin gene, tox, and its regulatory element, dtxR, by direct sequencing.

The largest diphtheria outbreak in the developed world since the 1960s is in progress in the Russian Federation. Seventy-two Corynebacterium diphtheriae strains from throughout Russia and the Ukraine, selected for temporal and geographic diversity, and 6 reference and control strains were assayed by DNA direct sequencing, and DNA sequences of their diphtheria toxin gene, tox, and the regulatory dtxR gene, were compared to those of the Park-Williams no. 8 strain (PW8).

Heterogeneity of diphtheria toxin gene, tox, and its regulatory element, dtxR, in Corynebacterium diphtheriae strains causing epidemic diphtheria in Russia and Ukraine.

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.

[Determination of the toxigenicity of Corynebacterium diphtheriae by using paper indicator disks].

The method for the determination of the toxigenicity of C. diphtheriae by means of discs impregnated with diphtheria antitoxin is proposed. The discs can be prepared long before use and stored for a year.