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Memorias Do Instituto Oswaldo Cruz 2020Bacillus anthracis is the aetiologic agent of anthrax, a re-emerging, septicaemic, haemorrhagic and lethal disease that affects humans, domestic ruminants and wildlife....
BACKGROUND
Bacillus anthracis is the aetiologic agent of anthrax, a re-emerging, septicaemic, haemorrhagic and lethal disease that affects humans, domestic ruminants and wildlife. Plasmids pXO1 and pXO2 are attributes that confer pathogenicity to B. anthracis strains. This bacterium was used as biological weapon in the World Wars and in the biological attack in the United States of America at 2001. B. anthracis is classified as a Tier 1 bioterrorism agent by the Centers for Diseases Control and Prevention. Anthrax is recognised as a re-emerging disease. Several studies concerning the dynamics of B. anthracis cycle in soil revealed that nonpathogenic B. anthracis strains due to lack of pXO2 plasmid are commonly found in some types of soil.
OBJECTIVES
This study aimed isolation and identification of B. anthracis spores in soil samples of the state of Rio de Janeiro, Brazil.
METHODS
Phenotypic and genotypic approaches were used to identify isolates including MALDI-TOF/MS, motility test, susceptibility to gamma phage and penicillin, survey for pag and cap genes as surrogates of pXO1 and pXO2 plasmids, respectively, and sequencing of 16SrRNA-encoding gene. Physicochemical analysis of the soil samples were carried out to describe soil characteristics.
FINDINGS
We observed the presence of one B. anthracis pXO1+ and pXO2- isolated from clay loam soil; one B. anthracis-like strain pXO1+ and pXO2-isolated from loamy sand; and 10 Bacillus spp. strains sensitive to phage-gamma that need better characterisation to define which their species were recovered from loamy sand.
MAIN CONCLUSIONS
This work showed promising results and it was the first study to report results from an active surveillance for B. anthracis in Brazil.
Topics: Antigens, Bacterial; Bacillus anthracis; Bacterial Toxins; Brazil; DNA, Bacterial; Humans; Plasmids; Polymerase Chain Reaction; Sequence Analysis, DNA; Soil; Soil Microbiology; Spores, Bacterial; Virulence; Virulence Factors
PubMed: 33174903
DOI: 10.1590/0074-02760200370 -
Revista Chilena de Infectologia :... Aug 2014
Topics: Bacillus anthracis
PubMed: 25327200
DOI: 10.4067/S0716-10182014000400012 -
Microbiology Spectrum Oct 2015In some Bacillus species, including Bacillus subtilis, the coat is the outermost layer of the spore. In others, such as the Bacillus cereus family, there is an... (Review)
Review
In some Bacillus species, including Bacillus subtilis, the coat is the outermost layer of the spore. In others, such as the Bacillus cereus family, there is an additional layer that envelops the coat, called the exosporium. In the case of Bacillus anthracis, a series of fine hair-like projections, also referred to as a "hairy" nap, extends from the exosporium basal layer. The exact role of the exosporium in B. anthracis, or for any of the Bacillus species possessing this structure, remains unclear. However, it has been assumed that the exosporium would play some role in infection for B. anthracis, because it is the outermost structure of the spore and would make initial contact with host and immune cells during infection. Therefore, the exosporium has been a topic of great interest, and over the past decade much progress has been made to understand its composition, biosynthesis, and potential roles. Several key aspects of this spore structure, however, are still debated and remain undetermined. Although insights have been gained on the interaction of exosporium with the host during infection, the exact role and significance of this complex structure remain to be determined. Furthermore, because the exosporium is a highly antigenic structure, future strategies for the next-generation anthrax vaccine should pursue its inclusion as a component to provide protection against the spore itself during the initial stages of anthrax.
Topics: Bacillus anthracis; Bacterial Proteins; Host-Pathogen Interactions; Microscopy, Electron, Transmission; Spores, Bacterial
PubMed: 26542035
DOI: 10.1128/microbiolspec.TBS-0021-2015 -
Virulence Nov 2013
Topics: Animals; Anthrax; Bacillus anthracis; Computational Biology; Humans; Molecular Diagnostic Techniques; Polymerase Chain Reaction
PubMed: 24067452
DOI: 10.4161/viru.26517 -
Toxins Aug 2015The interaction of anthrax toxin or toxin components with B. anthracis spores has been demonstrated. Germinating spores can produce significant amounts of toxin... (Review)
Review
The interaction of anthrax toxin or toxin components with B. anthracis spores has been demonstrated. Germinating spores can produce significant amounts of toxin components very soon after the initiation of germination. In this review, we will summarize the work performed that has led to our understanding of toxin and spore interactions and discuss the complexities associated with these interactions.
Topics: Animals; Antibodies, Fungal; Antigens, Bacterial; Bacillus anthracis; Bacterial Toxins; Humans; Macrophages; Spores, Bacterial
PubMed: 26287244
DOI: 10.3390/toxins7083167 -
Trends in Microbiology Jun 2014The pathophysiological effects resulting from many bacterial diseases are caused by exotoxins released by the bacteria. Bacillus anthracis, a spore-forming bacterium, is... (Review)
Review
The pathophysiological effects resulting from many bacterial diseases are caused by exotoxins released by the bacteria. Bacillus anthracis, a spore-forming bacterium, is such a pathogen, causing anthrax through a combination of bacterial infection and toxemia. B. anthracis causes natural infection in humans and animals and has been a top bioterrorism concern since the 2001 anthrax attacks in the USA. The exotoxins secreted by B. anthracis use capillary morphogenesis protein 2 (CMG2) as the major toxin receptor and play essential roles in pathogenesis during the entire course of the disease. This review focuses on the activities of anthrax toxins and their roles in initial and late stages of anthrax infection.
Topics: Animals; Anthrax; Antigens, Bacterial; Bacillus anthracis; Bacterial Toxins; Host-Pathogen Interactions; Humans; Mice; Models, Biological; Receptors, Peptide
PubMed: 24684968
DOI: 10.1016/j.tim.2014.02.012 -
Journal of Applied Microbiology Nov 2014Decontaminating large, outdoor spaces of Bacillus anthracis spores presents significant problems, particularly in soil. Proof was sought that the addition of germinant...
AIMS
Decontaminating large, outdoor spaces of Bacillus anthracis spores presents significant problems, particularly in soil. Proof was sought that the addition of germinant chemicals could cause spores of B. anthracis and Bacillus thuringiensis, a commonly used simulant of the threat agent, to convert to the less resistant vegetative form in a microcosm.
METHODS AND RESULTS
Nonsterile plant/soil microcosms were inoculated with spores of B. thuringiensis and two nonpathogenic strains of B. anthracis. A combination of L-alanine (100 mmol l(-1)) and inosine (10 mmol l(-1)) resulted in a 6 log decrease in spore numbers in both strains of B. anthracis over 2 weeks at 22°C; a 3 log decrease in B. anthracis Sterne spore numbers was observed after incubation for 2 weeks at 10°C. Negligible germination nor a decrease in viable count occurred in either strain when the concentration of L-alanine was decreased to 5 mmol l(-1). Germinated spores of B. thuringiensis were able to persist in vegetative form in the microcosms, whereas those of B. anthracis rapidly disappeared. The pleiotropic regulator PlcR, which B. anthracis lacks, does not contribute to the persistence of B. thuringiensis in vegetative form in soil.
CONCLUSIONS
The principle of adding germinants to soil to trigger the conversion of spores to vegetative form has been demonstrated. Bacillus anthracis failed to persist in vegetative form or resporulate in the microcosms after it had been induced to germinate.
SIGNIFICANCE AND IMPACT OF THE STUDY
The large scale, outdoor decontamination of B. anthracis spores may be facilitated by the application of simple, defined combinations of germinants.
Topics: Alanine; Bacillus anthracis; Bacillus thuringiensis; Decontamination; Inosine; Soil Microbiology; Spores, Bacterial
PubMed: 25099131
DOI: 10.1111/jam.12620 -
BMC Medicine Oct 2013The development of cardiovascular dysfunction and shock in patients with invasive Bacillus anthracis infection has a particularly poor prognosis. Growing evidence... (Review)
Review
The development of cardiovascular dysfunction and shock in patients with invasive Bacillus anthracis infection has a particularly poor prognosis. Growing evidence indicates that several bacterial components likely play important pathogenic roles in this injury. As with other pathogenic Gram-positive bacteria, the B. anthracis cell wall and its peptidoglycan constituent produce a robust inflammatory response with its attendant tissue injury, disseminated intravascular coagulation and shock. However, B. anthracis also produces lethal and edema toxins that both contribute to shock. Growing evidence suggests that lethal toxin, a metalloprotease, can interfere with endothelial barrier function as well as produce myocardial dysfunction. Edema toxin has potent adenyl cyclase activity and may alter endothelial function, as well as produce direct arterial and venous relaxation. Furthermore, both toxins can weaken host defense and promote infection. Finally, B. anthracis produces non-toxin metalloproteases which new studies show can contribute to tissue injury, coagulopathy and shock. In the future, an understanding of the individual pathogenic effects of these different components and their interactions will be important for improving the management of B. anthracis infection and shock.
Topics: Animals; Anthrax; Antigens, Bacterial; Bacillus anthracis; Bacterial Toxins; Cardiovascular Diseases; Humans; Metalloproteases; Shock
PubMed: 24107194
DOI: 10.1186/1741-7015-11-217 -
PloS One 2015There is a lack of data for how the viability of biological agents may degrade over time in different environments. In this study, experiments were conducted to...
There is a lack of data for how the viability of biological agents may degrade over time in different environments. In this study, experiments were conducted to determine the persistence of Bacillus anthracis and Bacillus subtilis spores on outdoor materials with and without exposure to simulated sunlight, using ultraviolet (UV)-A/B radiation. Spores were inoculated onto glass, wood, concrete, and topsoil and recovered after periods of 2, 14, 28, and 56 days. Recovery and inactivation kinetics for the two species were assessed for each surface material and UV exposure condition. Results suggest that with exposure to UV, decay of spore viability for both Bacillus species occurs in two phases, with an initial rapid decay, followed by a slower inactivation period. The exception was with topsoil, in which there was minimal loss of spore viability in soil over 56 days, with or without UV exposure. The greatest loss in viable spore recovery occurred on glass with UV exposure, with nearly a four log10 reduction after just two days. In most cases, B. subtilis had a slower rate of decay than B. anthracis, although less B. subtilis was recovered initially.
Topics: Bacillus anthracis; Bacillus subtilis; Dose-Response Relationship, Radiation; Kinetics; Microbial Viability; Porosity; Species Specificity; Spores, Bacterial; Ultraviolet Rays
PubMed: 26372011
DOI: 10.1371/journal.pone.0138083 -
Journal of Bacteriology Feb 2011Bacillus anthracis shares many regulatory loci with the nonpathogenic Bacillus species Bacillus subtilis. One such locus is sinIR, which in B. subtilis controls...
Bacillus anthracis shares many regulatory loci with the nonpathogenic Bacillus species Bacillus subtilis. One such locus is sinIR, which in B. subtilis controls sporulation, biofilm formation, motility, and competency. As B. anthracis is not known to be motile, to be naturally competent, or to readily form biofilms, we hypothesized that the B. anthracis sinIR regulon is distinct from that of B. subtilis. A genome-wide expression microarray analysis of B. anthracis parental and sinR mutant strains indicated limited convergence of the B. anthracis and B. subtilis SinR regulons. The B. anthracis regulon includes homologues of some B. subtilis SinR-regulated genes, including the signal peptidase gene sipW near the sinIR locus and the sporulation gene spoIIE. The B. anthracis SinR protein also negatively regulates transcription of genes adjacent to the sinIR locus that are unique to the Bacillus cereus group species. These include calY and inhA1, structural genes for the metalloproteases camelysin and immune inhibitor A1 (InhA1), which have been suggested to be associated with virulence in B. cereus and B. anthracis, respectively. Electrophoretic mobility shift assays revealed direct binding of B. anthracis SinR to promoter DNA from strongly regulated genes, such as calY and sipW, but not to the weakly regulated inhA1 gene. Assessment of camelysin and InhA1 levels in culture supernates from sinR-, inhA1-, and calY-null mutants showed that the concentration of InhA1 in the culture supernatant is inversely proportional to the concentration of camelysin. Our data are consistent with a model in which InhA1 protease levels are controlled at the transcriptional level by SinR and at the posttranslational level by camelysin.
Topics: Bacillus anthracis; Bacterial Proteins; DNA, Bacterial; Electrophoretic Mobility Shift Assay; Gene Deletion; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Metalloendopeptidases; Operon; Peptide Hydrolases; Promoter Regions, Genetic; Protein Binding; Regulon; Repressor Proteins
PubMed: 21131488
DOI: 10.1128/JB.01083-10