Showing papers on "Bacillus anthracis published in 1992"
TL;DR: The application of newly available DNA probe, polymerase chain reaction and specific toxin antigen detection technology has revealed that a proportion of strains isolated during epidemiological investigations are B. anthracis which lack the plasmid carrying the capsule gene (pXO2).
Abstract: Gram-positive bacilli isolated during epidemiological investigations which, on the basis of conventional tests, resemble Bacillus anthracis but which fail to produce the capsule or to induce anthrax in test animals have long been dismissed in clinical and veterinary laboratories as B. cereus or simply as unidentified Bacillus spp. and thereupon discarded as inconsequential. In this study, the application of newly available DNA probe, polymerase chain reaction and specific toxin antigen detection technology has revealed that a proportion of such strains are B. anthracis which lack the plasmid carrying the capsule gene (pXO2). While these techniques cannot, of course, be used to confirm the identities of strains resembling B. anthracis but which also lack the plasmid carrying the toxin genes (pXO1), the likelihood that these also are bonajide B. anthracis becomes more acceptable. (As yet no naturally occurring pXOl-/2+ strains have been found.) At this point, the significance of the presence of such avirulent forms of B. anthracis in specimens can only be a subject for speculation, but the possibility that they may be indicators of virulent parents somewhere in the system being examined must be considered.
154 citations
TL;DR: In this paper, the effectiveness of immunization against anthrax with Bacillus anthracis protective antigen (PA) combined with different adjuvants was tested in Hartley guinea pigs and CBA/J and A/J mice.
Abstract: The protective efficacy of immunization against anthrax with Bacillus anthracis protective antigen (PA) combined with different adjuvants was tested in Hartley guinea pigs and CBA/J and A/J mice. Adjuvant components derived from microbial products that were tested included threonyl-muramyl dipeptide (threonyl-MDP); monophosphoryl lipid A (MPL); trehalose dimycolate (TDM); and the delipidated, deproteinized, cell wall skeleton (CWS) from either Mycobacterium phlei or the BCG strain of Mycobacterium bovis. Non-microbially derived adjuvants tested included aluminum hydroxide and the lipid amine CP-20,961. In guinea pigs, all adjuvants and adjuvant mixtures enhanced antibody titers to PA as well as survival after a parenteral challenge of virulent B. anthracis Ames spores. In contrast, PA alone or combined with either aluminum hydroxide or CP-20,961 failed to protect mice. Vaccines containing PA combined with threonyl-MDP or MPL-TDM-CWS protected a majority of female CBA/J mice. Statistical analysis of survival data in the guinea pigs indicated that PA-MPL-CWS and PA-MPL-TDM-CWS were more efficacious than the currently licensed human anthrax vaccine.
130 citations
TL;DR: The primary structures of the 23S ribosomal RNA genes of Bacillin anthracis and an emetic strain of Bacillus cereus were determined by direct sequencing of enzymatically amplified chromosomal DNA and the feasibility of using PCR-direct sequencing for the rapid sequence determination of large-subunit rRNA genes is demonstrated.
Abstract: The primary structures of the 23S ribosomal RNA genes of Bacillus anthracis and an emetic strain of Bacillus cereus were determined by direct sequencing of enzymatically amplified chromosomal DNA. The 23S rRNA gene sequences of B. anthracis and B. cereus were found to be almost identical and showed only two differences (a single nucleotide change, and a single base insertion in B. cereus). The feasibility of using PCR-direct sequencing for the rapid sequence determination of large-subunit rRNA genes is demonstrated.
126 citations
TL;DR: Serological findings from studies on sera from a group of 62 human anthrax patients in Turkey and from cattle in Britain following two unrelated outbreaks of anthrax show that EIA using protective antigen can be a useful diagnostic aid and will detect subclinical infections in appropriate circumstances.
Abstract: Results are presented from a number of epidemiological studies using enzyme immunoassays (EIA) based on the purified anthrax toxin antigens, protective antigen, lethal factor and oedema factor. Studies on sera from a group of 62 human anthrax patients in Turkey and from cattle in Britain following two unrelated outbreaks of anthrax show that EIA using protective antigen can be a useful diagnostic aid and will detect subclinical infections in appropriate circumstances. A serological survey on wildlife in the Etosha National Park, Namibia, where anthrax is endemic, showed that naturally acquired anthrax-specific antibodies are rare in herbivores but common in carnivores; in carnivores, titres appear to reflect the prevalence of anthrax in their ranges. Problems, as yet unresolved, were encountered in studies on sera from pigs following an outbreak of anthrax on a farm in Wales. Clinical details, including treatment, of the human and one of the bovine outbreaks are summarized and discussed in relation to the serological findings.
102 citations
TL;DR: It is found that, in the blood of infected animals, the protective antigen exists primarily as a 63 kDa protein and appears to be complexed with the lethal factor component of the toxin.
Abstract: Summary: The protective antigen component of anthrax lethal toxin, produced in vitro, has a molecular mass of 83 kDa. Cell-culture studies by others have demonstrated that upon binding of the 83 kDa protective antigen to cell-surface receptors, the protein is cleaved by an unidentified cell-associated protease activity. The resultant 63 kDa protein then binds lethal factor to form lethal toxin, which has been proposed to be internalized by endocytosis. We found that, in the blood of infected animals, the protective antigen exists primarily as a 63 kDa protein and appears to be complexed with the lethal factor component of the toxin. Conversion of protective antigen from 83 to 63 kDa was catalysed by a calcium-dependent, heat-labile serum protease. Except for being complexed to protective antigen, there was no apparent alteration of lethal factor during the course of anthrax infection. The protective antigen-cleaving protease appeared to be ubiquitous among a wide range of animal species, including primates, horses, goats, sheep, dogs, cats and rodents.
100 citations
TL;DR: These protease-treated preparations of PA should prove useful in both elucidating the intracellular processing of anthrax lethal toxin and determining the structure-function relationship of PA and LF.
77 citations
56 citations
TL;DR: A transcriptional fusion between the promoter region of the PA gene (pag) and the lacZ gene was constructed and introduced into Bacillus anthracis Sterne and expression from the pag promoter was observed throughout exponential-phase and was maximal in early stationary phase.
Abstract: The production of protective antigen (PA), the common component of the two anthrax toxins, is influenced by the environment. In order to examine factors involved in its regulation, a transcriptional fusion between the promoter region of the PA gene (pag) and the lacZ gene was constructed and introduced into Bacillus anthracis Sterne. Activity of the pag promoter was followed by measuring β-galactosidase activities under various growth and medium conditions. Expression from the pag promoter was observed throughout exponential-phase and was maximal in early stationary phase. The activity of the pag promoter was stimulated by the addition of glucose in the medium.
36 citations
TL;DR: The polymerase chain reaction (PCR) was used to identify spores of Bacillus anthracis, and subjecting the product of this PCR to a second PCR designed to amplify a 208-bp fragment nested within the 1247-bp product improved detection.
Abstract: The polymerase chain reaction (PCR) was used to identify spores of Bacillus anthracis. By using an assay capable of amplifying a 1247-bp fragment from the gene that encodes the edema factor of B. anthracis, as few as 10(3) copies of a plasmid containing the edema factor gene and as few as 2 x 10(4) spores were detected. Subjecting the product of this PCR to a second PCR designed to amplify a 208-bp fragment nested within the 1247-bp product improved detection to a single plasmid copy per PCR and to two spores of B. anthracis per PCR.
34 citations
Journal Article•
TL;DR: High therapeutic efficacy of minocycline in the average therapeutic concentrations was shown irrespective of the contaminating doses and strains, and minocyCline was recommended for treatment and urgent prophylaxis of anthracic infection caused by tetracycline-resistant B. anthracis strains.
Abstract: In vivo and in vitro efficacy of tetracyclines was studied with respect to anthracic infection induced by a tetracycline-resistant resistant strain containing plasmid pBC16. The plasmid-containing strain was resistant to tetracycline, doxycycline and minocycline, the MICs exceeding those for the initial strain 500, 640 and 80 times, respectively. There was no therapeutic effect of tetracycline and doxycycline in the treatment and urgent prophylaxis of anthracic infection caused by the tetracycline-resistant strain of Bacillus anthracis. High therapeutic efficacy of minocycline in the average therapeutic concentrations was shown irrespective of the contaminating doses and strains. Minocycline was recommended for treatment and urgent prophylaxis of anthracic infection caused by tetracycline-resistant B. anthracis strains.
29 citations
TL;DR: This work examined one male and two female patients with a localised itchy erythematous papule of the eyelid with anthrax, and a necrotising ulcer formed in each of the three cases resulting in a black lesion.
Abstract: Anthrax is a disease caused by Bacillus anthracis. The disease affects primarily herbivores including sheep, cattle, horses, and other domestic animals. Humans may rarely be affected. We examined one male and two female patients with a localised itchy erythematous papule of the eyelid. A necrotising ulcer formed in each of the three cases resulting in a black lesion. Scraping in each case showed Gram positive rods and culture grew Bacillus anthracis. All three patients responded to the intravenous administration of penicillin G, and the lesion resolved leaving scars in two cases. Anthrax is a rare disease but should be considered in the differential diagnosis of ulcers or pustules of the eyelids.
TL;DR: Tests for antibodies against protective antigen and lethal factor using EIA and Western blot techniques were positive in three subjects (in paired sera) with cutaneous anthrax and in one subject who neither had had direct contact with the infected cow nor showed any sign of anthrax.
Abstract: Three cases of cutaneous anthrax are reported which occurred in a farming family in northern Italy. Epidemiological studies revealed contact with an infected cow (delivery of a stillborn fetus and slaughter). The cow was slaughtered soon after the delivery; cultures of carcass specimens yielded growth ofBacillus anthracis. The origin of the animal infection was not known. Serum samples were obtained from all 11 members of the family group and randomly from 10 of the 75 cows on the farm, which appeared to be in good health. Tests for antibodies against protective antigen and lethal factor using EIA and Western blot techniques were positive in three subjects (in paired sera) with cutaneous anthrax and in one subject who neither had had direct contact with the infected cow nor showed any sign of anthrax.
TL;DR: The new attenuated recombinants, engineered so that they can not revert to a fully virulent form, may serve as new live vaccine candidates.
Abstract: Since 1980, following the Sverdlovsk incident, there has been an enormous resurgence in research activity on both the nature of Bacillus anthracis and the tripartite toxin it elaborates. A plasmid, pXO1, has been shown to control the production of the toxin components; protective antigen, edema factor and lethal factor. Another plasmid, pXO2, encodes for the protective capsule that inhibits phagocytosis. The mechanism of action of edema factor has been identified as that of an adenylate cyclase. Along with major advances in molecular biology a number of very promising recombinant constructs have been made that shed new light of the role of individual components. The new attenuated recombinants, engineered so that they can not revert to a fully virulent form, may serve as new live vaccine candidates.
01 Jan 1992
TL;DR: The first bacterial vaccines were Pasteur's attenuated strains of Pasteurella multocida and Bacillus anthracis, but until recently there has been relatively little effort to develop or use such strains for protection of humans, with the conspicuous exception of strain BCG.
Abstract: The first bacterial vaccines were Pasteur’s attenuated strains of Pasteurella multocida and Bacillus anthracis, but until recently there has been relatively little effort to develop or use such strains for protection of humans, with the conspicuous exception of strain BCG, for prevention of tuberculosis.