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PubMed1972

Diphtheria in Iran.

A study of diphtheria in Iran was undertaken during the summer of 1969. Diphtheria was found to be more common among the younger people and to reach its peak 3 months after the start of the school term, during the coldest period of the year. Owing to the liberal use of antibiotics a number of modified clinical cases were observed. Of the strains isolated, 89.7% were gravis, 1.3% intermedius and 9% mitis. Phage typing of these strains showed that the mitis and intermedius strains could only be typed by adapted phages and the majority of gravis strains were phage type XIV, which is the epidemic type seen in other countries.As the mass immunization campaign reduces the incidence of diphtheria in Iran, the epidemiological pattern of the disease will change as seen in the U.K. and U.S.A. It is, therefore, suggested that in the future further studies of diphtheria in Iran be undertaken in order to provide us with information about the changing epidemiological pattern of the disease.

Age Factors↗
PubMed1984

Diphtheria in North America.

The incidence of diphtheria has declined in North America during the last fifty years until it is now an uncommon disease. This general pattern is similar to that seen in other developed countries with well-organized immunization programmes, but certain noteworthy characteristics have been observed in recent years: foci of infection lingered in two population groups of low socio-economic status, in both of which the skin has been an important reservoir. In central areas of certain cities, endemic diphtheria, chiefly cutaneous, has occurred amongst indigent adult males living in unhygienic conditions; and in the native Indian population of Northern Canada diphtheria infection has been endemic in infants and children, many of the infections being of the skin or ear and toxic disease being uncommon. During the last few years, diphtheria outbreaks have not been reported in urban areas and possibly endemicity is now restricted to northern native populations. The number of infections detected in these northern endemic areas is steadily decreasing.

Adolescent↗
PubMed2003

Diphtheria immunization rates and the effect of several sociodemographic factors on immunization of children in eastern Turkey.

BACKGROUND: One of the aims of the World Health Organization is to eliminate diphtheria in all countries. Thus, it is important to achieve a high level of childhood immunization. The present study was performed to determine the level of child immunization against diphtheria and the effect of several sociodemographic factors on immunization of children aged 0-6 years. METHODS: Using the cluster-sampling method, 767 healthy children were selected at random from three provinces in eastern Turkey. Children were categorized as completely vaccinated, incompletely vaccinated, unvaccinated or vaccination status unknown. If the child had no immunization card, he/she was categorized as vaccination status unknown. RESULTS: Of the 767 children, 72.3% were completely vaccinated, 18.3% were incompletely vaccinated and 5.7% were not vaccinated. Vaccination status was unknown for 3.7% of children. As the age of the children increased, the proportion of completely vaccinated children increased and the proportion of non-vaccinated and incompletely vaccinated children decreased. The vaccination rates increased in parallel with the education level of the parents. While the vaccination rate was significantly correlated with the socioeconomic level of the families, it was inversely correlated with sibling number. CONCLUSIONS: The results of the present study show that the immunization status necessary for the elimination of diphtheria has not yet been reached in eastern Turkey. In immunization programs for children in eastern Turkey, priority should be given to increasing primary immunization levels to 90-95% with three or more doses of diphtheria toxoid.

Child↗
PubMed2001

[Prevention of diphtheria in Germany: yesterday, today, tomorrow - an overview].

The year 2000 was the first without the registration of any cases of diphtheria in Germany. However, serologic protection against diphtheria amongst the population is very low, especially among young and middle-aged adults, where over 50 % are not or only minimally protected. In a review of the diphtheria cases of the last 7 years (n = 18), three factors were associated with the disease: adult age (14 cases between 18 and 50 years of age), travelling (in 14 of 18 cases travelling to or from endemic areas played a role) and occupational exposure (suspected in 6 of 18 cases). In Germany, the official guidelines which suggest a booster vaccination every ten years are followed very insufficiently. Should vaccination habits fail to improve, population immunity will further decrease and a resurgence of diphtheria will become more likely. Measures for future preventive activities are being discussed.

Adolescent↗
PubMed1981

[Varieties of diphtheria: microbiological diagnosis and epidemiological observations (author's transl)].

Following several cases of diphtheria an epidemiological investigation was made in and around Aachen. A total of 1458 throat and nose smears were examined for various Corynebacteria species. Other than in two patients who had diphtheria, toxin-producing Corynebacterium diphtheriae was demonstrated in only one person who had been in immediate contact with them. Of a total of 150 Corynebacteria of different species which were isolated, two further isolates proved to be non-toxin-producing diphtheria bacteria. All five strains were found in foreigners, who represented 46.8% of all tested subjects. The number of isolated Corynebacteria of different species was, at 13.62%, almost double that in a group of non-foreigners (7.35%).

Child↗
PubMed1974

Synthesis of diphtheria tox-gene products in Escherichia coli extracts.

In a protein-synthesizing system extracted from E. coli, purified DNA from corynephages betac(tox+) and beta45c was used to direct the in vitro synthesis of diphtheria toxin and of the related nontoxic protein, CRM45, as well as of other beta-phage proteins. When betac(tox+)-DNA or betac-DNA was added to a similar system extracted from the nonlysogenic Corynebacterium diphtheriae strain, C7(s)(-)(tox-), neither toxin nor the CRM45 protein was produced, although other beta-phage proteins were synthesized in amounts equivalent to those produced in the E. coli system from the same amount of beta-phage DNA. Preliminary experiments suggest that both toxinogenic and nontoxinogenic strains of the diphtheria bacillus contain a factor that specificially blocks expression of the tox gene. Synthesis of toxin and the CRM45 protein in the E. coli system could not be inhibited by relatively high concentrations of inorganic iron, but could be inhibited by extracts from the C7(s)(-)(tox-) strain of C. diphtheriae.

Amino Acids↗
PubMed1993

A diphtheria epidemic in Lesotho, 1989. Did vaccination increase the population's susceptibility?

We report a diphtheria outbreak which occurred in the 1st 6 months of 1989 in the Quthing district of Lesotho in Southern Africa. Sixty-eight clinical cases were identified in patients with ages ranging from 14 months to 51 years. The 10-15-year age group represented 38% of the cases and the 15-20-year age group another 26%. Age-adjusted incidence rates were higher in patients aged between 15 and 35 than in those aged 0-15 years (p < 0.001). The overall case fatality rate was 23%. Most deaths occurred in the age range 10-14 years, but the case fatality rate tended to be higher in the younger age groups. The epidemic raises the question of the influence of the ongoing vaccination programme, established since 1977, and the importance of naturally acquired immunity. It is suggested that the number of throat carriers, who in the absence of skin diphtheria would provide most of the population's immunity, decreases as an indirect consequence of vaccination, and that certain groups not immediately reached by vaccination become more susceptible to diphtheria. This outbreak also illustrates that a sporadic case of diphtheria in a partially immunized community warrants serious efforts to curb the spread of the disease.

Adolescent↗
PubMed1956

Transfer of delayed hypersensitivity to diphtheria toxin in man.

Simultaneous transfer of delayed hypersensitivity to diphtheria toxin and to tuberculin has been accomplished in eight consecutive instances in man using extracts from washed leucocytes taken from the peripheral blood of tuberculin-positive, Schick-negative donors who were highly sensitive (i.e., pseudoreactors) to purified diphtheria toxin and toxoid. The leucocyte extracts used for transfer contained no detectable antitoxin. The recipient subjects were Schick-positive (<0.001 unit antitoxin per ml. serum) and tuberculin-negative at the time of transfer. All the recipients remained Schick-positive for at least 2 weeks following transfer and in every case their serum contained less than 0.001 units antitoxin at the time when they exhibited maximal skin reactivity to toxoid. Evidence is presented which indicates that the transfer factor may be released from leucocyte suspensions under mild conditions in which most of the cells appear to remain morphologically intact. Four adult Schick-positive subjects have been sensitized to diphtheria toxoid by intradermal injection of a few micrograms of purified toxoid in the form of a washed toxoid-antitoxin precipitate. Two of these sensitized individuals showed severe delayed skin reactions specifically directed against diphtheria toxin (or toxoid) at a time when their serum antitoxin level was less than 0.001 units/ml.

Adult↗
PubMed2000

The changing epidemiology of diphtheria in the vaccine era.

The epidemic of diphtheria in the Newly Independent States (NIS) of the former Soviet Union has drawn attention to our incomplete understanding of the epidemiology of diphtheria. Many unanswered questions remain concerning the reasons for a resurgence of diphtheria and for the shift in the age of patients and concerning the mechanisms for acquisition of immunity in adults through natural infection under unfavorable living conditions. Other unanswered questions relate to the precise role of socioeconomic factors and hygiene conditions in the initiation, buildup, and spread of the epidemic. Important characteristics of the NIS epidemic can be used to help predict the spread of future diphtheria epidemics. These characteristics include a high proportion of infected adults, a progressive spread of disease from urban centers to rural areas, and transition from initial amplification of disease in groups with high rates of close contacts in focalized, well-distinguished outbreaks to a more generalized epidemic.

Age Distribution↗
PubMed2000

The European Laboratory Working Group on Diphtheria: A global microbiologic network.

Increasing international travel, migration to and from epidemic areas, and the emergence of epidemic Corynebacterium diphtheriae strains globally have highlighted the need for better microbiologic surveillance and greater clinical and laboratory awareness. As part of the strategy developed by the World Health Organization, one major goal is particularly applicable to the microbiology and epidemiology of diphtheria: to improve surveillance for early detection of emerging and reemerging diseases by establishing a network of national and international laboratories. The European Laboratory Working Group on Diphtheria (ELWGD) was therefore formed in 1993 as a result of the epidemic situation in Eastern Europe. Currently, there is participation from 20 different countries from Western and Eastern Europe, the United States, Australia, and Southeast Asia. ELWGD is a prime example of a collaborative and coordinated approach to the microbiology of diphtheria and should serve as a potential model for other infectious diseases networks.

Corynebacterium diphtheriae↗
PubMed1994

Nontoxigenic Corynebacterium diphtheriae isolated from intravenous drug users.

During a prospective study 117 intravenous drug users were screened for infection with Corynebacterium diphtheriae. Nontoxigenic C. diphtheriae was found in 5 of 132 throat swab specimens and in 5 of 28 skin ulcer specimens taken from July 1991 to April 1992. When phenotypic and molecular typing methods were used, these 10 strains were shown to belong to a single clone. During the same period no strain was isolated from 200 controls. Clinical manifestations of infection were not clearly attributable to C. diphtheriae--no typical membranous pharyngitis was present. The presence of a single clone among homeless intravenous drug users in Zurich indicates the presence of C. diphtheriae in parts of the population with poor standards of hygiene and low socioeconomic status.

Adult↗
PubMed2003

Molecular epidemiology and characteristics of Corynebacterium diphtheriae and Corynebacterium ulcerans strains isolated in Italy during the 1990s.

Five cases of diphtheria were reported in Italy between January 1990 and June 2001. Three cases were confirmed microbiologically by the isolation of toxigenic Corynebacterium diphtheriae (two cases) and Corynebacterium ulcerans (one case). Over the same period, 11 cases of non-toxigenic C. diphtheriae infection were reported to the Italian Public Health Institute, from which the causative organism was isolated from a skin infection in one case and from the throat in the other ten. Seven of the throat isolates were associated with fever, severe pharyngitis and tonsillitis and were all biotype gravis. Because there are no standardized breakpoints, the antimicrobial sensitivities of C. diphtheriae were determined in accordance with the National Committee for Clinical Laboratory Standards guidelines for Streptococcus spp. other than Streptococcus pneumoniae. MICs for penicillin ranged between 0.125 and 0.250 mg l(-1) and 7 out of 11 strains had a minimal bactericidal concentration (MBC)/MIC ratio >or= 32. All strains were sensitive to clindamycin (MIC <or= 0.25 mg l(-1)), rifampicin (MIC <or= 1 mg l(-1)) and tetracycline (MIC <or= 2 mg l(-1)), and showed moderate susceptibility to cefotaxime (MIC 0.75-1.5 mg l(-1)). Molecular typing (ribotyping) demonstrated the presence of several distinct ribotypes. The ribotype designated 'D11' has been documented amongst strains isolated in the UK, Russia, Germany, Romania and Sweden. Ribotype 'D75' has only been documented in the UK. The C. ulcerans strain had a ribotype pattern identical to that found in recent isolates from the UK.

Colony Count, Microbial↗
PubMed1999

Characterization of surface saccharides in two Corynebacterium diphtheriae strains.

Two Corynebacterium diphtheriae strains were analyzed by assays employing a battery of highly purified fluorescent lectins. From 22 lectins tested only seven with affinity to receptor molecules containing N-acetylglucosamine (D-GlcNAc), N-acetylgalactosamine (D-GalNAc), galactose (D-Gal), mannose-like (D-Man-like) and sialic acid residues showed positive fluorescent labeling. A higher reactivity of Triticum vulgaris (WGA), which binds to sialic acid and/or beta-D-GlcNAc-containing residues, and Bandeiraea simplicifolia II (BS-II), which recognizes alpha and beta-D-GlcNAc units, was shown by the sucrose-fermenting strain. Ricinus communis (RCA-I), which recognizes D-Gal units in addition to both Glycine max (SBA) and Artocarpus integrifolia (Jacaline) agglutinins that bind to D-GalNAc-containing residues, reacted preferentially with the sucrose-negative strain. Canavalia ensiformis (Con A), which recognizes D-Man-like receptors, reacted with both sucrose-fermenting and non-sucrose-fermenting C. diphtheriae biotypes. However, higher interaction was observed with the non-sucrose-fermenting strain. Fluorescence of WGA binding was significantly decreased by neuraminidase treatment suggesting the presence of an exposed sialic acid moiety on C. diphtheriae surfaces. Binding assay using radiolabeled [125I]WGA essentially confirmed the lectin fluorescence studies. N-Acetylneuraminic acid moieties were detected in whole cell hydrolysates as assessed by thin-layer and gas-liquid chromatography. The data indicate differences on the cell surface saccharide ligands between the sucrose-fermenting and the non-sucrose-fermenting C. diphtheriae strains.

Chromatography, Gas↗
PubMed2002

Intracellular viability of toxigenic Corynebacterium diphtheriae strains in HEp-2 cells.

Corynebacterium diphtheriae, generally considered an extracellular coloniser, was evaluated for its ability to enter and survive within HEp-2 monolayers by gentamicin protection assay. Intracellular viability of HC01 strain, isolated from endocarditis, was more expressive (2.59%) than observed in 241 (0.21%) and CDC-E8392 (1.93%) strains. Electron microscopy of C. diphtheriae-infected HEp-2 cells revealed intracellular bacteria inside membrane-bound vacuoles. Bacterial internalisation was totally inhibited by 5 microM cytochalasin E and significantly inhibited by 100 microM genistein (P<0.05). Therefore, C. diphtheriae presents the ability to survive within cultured epithelial cells and signalling cascade as well as actin polymerisation are required for entry of diphtheria bacilli into HEp-2 cells.

Anti-Bacterial Agents↗
PubMed1996

Fall-off in immunity following diphtheria revaccination--an 8 year follow-up study.

Diphtheria may occur even among previously vaccinated persons and knowledge of the duration of immunity is of crucial importance when designing effective vaccination programmes. In a follow-up study of 42 representative probands revaccinated 8 years previously, a continuous fall-off in antitoxic immunity was demonstrated. 98% were still protected (antitoxin concentration > 0.01 IU/ml). From the distribution of titres in the group the individual risk of susceptibility 8 years after revaccination was calculated to be 0.8/1000 (0.2-2.9/1000, 95% confidence limits). Thus, repeated revaccinations are required to secure continuous protection. The fall-off pattern for diphtheria antitoxin was approximately the same as for tetanus antitoxin. Peak values following revaccination are decisive for the duration of immunity. As peak values following vaccination depend on naturally acquired immunity and consequently decrease as indigenous diphtheria in a population disappears, highly potent vaccines are required to secure long-term immunity following diphtheria revaccination. The effects of dose and adjuvant are discussed.

Adult↗
PubMed1972

Reconstitution of diphtheria toxin from two nontoxic cross-reacting mutant proteins.

The isolation of a new type of mutant Corynephage beta, which carries a missense mutation in the structural gene for diphtheria toxin synthesis is described. The lysogenic C7(8)(beta(197))(tox-crm+) strain of Corynebacterium diphtheriae produces a nontoxic, extracellular protein of molecular weight 62,000. This protein is immunologically indistinguishable from toxin itself but inhibits the action of toxin on HeLa cells, probably by competing for attachment sites on the cell membrane. In contrast to fragment A derived from diphtheria toxin, fragment A(197) is unable to catalyze the inactivation of eucaryotic polypeptidyl-transfer RNA-transferase II. When mixtures of the two nontoxic mutant proteins, enzymically active crm(45) protein and enzymically inactive crm(197) protein, are subjected to mild treatment with trypsin in the presence of a thiol and then allowed to reoxidize after dialysis to remove excess thiol, "diphtheria toxin" is reconstituted in high yield.

Adenosine Diphosphate↗
PubMed1971

Polyacrylamide gel electrophoresis of Corynebacterium diphtheriae: a possible epidemiological aid.

In this preliminary study, the use of polyacrylamide gel electrophoresis as an aid in the characterization of Corynebacterium diphtheriae was evaluated and a standardized method was developed. The electrophoretic patterns of 17 gravis, 14 mitis, and 2 intermedius types of C. diphtheriae were compared with the electrophoretic patterns of 5 Robinson and Peeney stock gravis serotype strains. Each of the 5 stock serotype strains had different electrophoretic patterns, although some common bands were present. The 17 gravis strains isolated in the United States showed patterns identical to those of the stock gravis serotype II strain. The 14 mitis strains examined produced 6 different electrophoretic patterns, irrespective of geographical location. One mitis pattern corresponded with the pattern of gravis serological type II. The two intermedius strains examined had identical electrophoretic patterns that resembled the pattern of gravis serotype IV. Polyacrylamide gel electrophoresis of C. diphtheriae strains may prove to be a useful epidemiologic tool in establishing the distribution and occurrence of various C. diphtheriae types.

Bacteriological Techniques↗
PubMed1983

Detection and expression of DNA homologous to the tox gene in nontoxinogenic isolates of Corynebacterium diphtheriae.

Three probes have been described which can be used to detect the presence of DNA sequences homologous to the tox gene of Corynebacterium diphtheriae. Probes "A" and "B" detected sequences coding for A and B fragments of diphtheria toxin, respectively. The third "A-B" probe contained both the A and B coding sequences. The B probe was completely unambiguous in detecting only toxin-related sequences, and the A probe was only slightly less so. The efficacy of the probes was tested on a series of toxinogenic and nontoxinogenic isolates of C. diphtheriae. All isolates which were toxinogenic as characterized by the gel immunodiffusion technique gave positive reactions with the probes. Of particular interest was the finding that 14 of 43 nontoxinogenic isolates also carried DNA homologous to both the A and B probes. All 14 isolates were nontoxinogenic by the rabbit intracutaneous test as well as by the gel immunodiffusion test; however, 12 of them produced ADP-ribosylating activity, whereas two were negative. The isolates producing ADP-ribosylating activity belonged to a cohort of cultures, of which 11 were isolated in South Dakota and 1 was isolated in Montana. Genomic DNAs of all 12 appeared to be identical when restriction enzyme digest patterns were compared, and the same fragment carried the tox gene in all of them. The tox-bearing nontoxinogenic isolates from Alaska and Florida each had unique restriction patterns and did not produce ADP-ribosylating activity. A number of genomic fragments of all the tox-bearing nontoxinogenic isolates hybridized with beta converting phage DNA. The significance of these observations to the natural history of diphtheria was discussed.

Bacteriophages↗