scholarly journals Aerosol and Surface Deposition Characteristics of Two Surrogates for Bacillus anthracis Spores

2016 ◽  
Vol 82 (22) ◽  
pp. 6682-6690 ◽  
Author(s):  
Alistair H. Bishop ◽  
Helen L. Stapleton
Keyword(s):  
Bacillus Anthracis ◽  
Pathogenic Bacteria ◽  
Human Infection ◽  
Solid Surfaces ◽  
Surface Deposition ◽  
Content Type ◽  
Hazard Management ◽  
Bacillus Anthracis Spores ◽  
Air Blower ◽  
Set Up

ABSTRACTSpores of an acrystalliferous derivative ofBacillus thuringiensissubsp.kurstaki, termedBtcry−, are morphologically, aerodynamically, and structurally indistinguishable fromBacillus anthracisspores.Btcry− spores were dispersed in a large, open-ended barn together with spores ofBacillus atrophaeussubsp.globigii, a historically used surrogate forBacillus anthracis. Spore suspensions (2 × 1012CFU each ofB. atrophaeussubsp.globigiiandBtcry−) were aerosolized in each of five spray events using a backpack misting device incorporating an air blower; a wind of 4.9 to 7.6 m s−1was also flowing through the barn in the same direction. Filter air samplers were situated throughout the barn to assess the aerosol density of the spores during each release. Trays filled with a surfactant in aqueous buffer were placed on the floor near the filter samplers to assess spore deposition. Spores were also recovered from arrays of solid surfaces (concrete, aluminum, and plywood) that had been laid on the floor and set up as a wall at the end of the barn.B. atrophaeussubsp.globigiispores were found to remain airborne for significantly longer periods, and to be deposited on horizontal surfaces at lower densities, thanBtcry− spores, particularly near the spray source. There was a 6-fold-higher deposition ofBtcry− spores than ofB. atrophaeussubsp.globigiispores on vertical surfaces relative to the surrounding airborne density. This work is relevant for selecting the bestB. anthracissurrogate for the prediction of human exposure, hazard assessment, and hazard management following a malicious release ofB. anthracis.IMPORTANCEThere is concern that pathogenic bacteria could be maliciously disseminated in the air to cause human infection and disruption of normal life. The threat from spore-forming organisms, such as the causative agent of anthrax, is particularly serious. In order to assess the extent of this risk, it is important to have a surrogate organism that can be used to replicate the dispersal characteristics of the threat agent accurately. This work compares the aerosol dispersal and deposition behaviors of the surrogatesBtcry− andB. atrophaeussubsp.globigii.Btcry− spores remained in the air for a shorter time, and were markedly more likely to adhere to vertical surfaces, thanB. atrophaeussubsp.globigiispores.

scholarly journals Behavior of Yersinia enterocolitica in the Presence of the Bacterivorous Acanthamoeba castellanii

2013 ◽  
Vol 79 (20) ◽  
pp. 6407-6413 ◽  
Author(s):  
E. Lambrecht ◽  
J. Baré ◽  
I. Van Damme ◽  
W. Bert ◽  
K. Sabbe ◽  
...  
Keyword(s):  
Yersinia Enterocolitica ◽  
Pathogenic Bacteria ◽  
Acanthamoeba Castellanii ◽  
Ecological Niches ◽  
Free Living ◽  
Content Type ◽  
Food Borne ◽  
Transmission Electron ◽  
Set Up ◽  
The Impact

ABSTRACTFree-living protozoa play an important role in the ecology and epidemiology of human-pathogenic bacteria. In the present study, the interaction betweenYersinia enterocolitica, an important food-borne pathogen, and the free-living amoebaAcanthamoeba castellaniiwas studied. Several cocultivation assays were set up to assess the resistance ofY. enterocoliticatoA. castellaniipredation and the impact of environmental factors and bacterial strain-specific characteristics. Results showed that allY. enterocoliticastrains persist in association withA. castellaniifor at least 14 days, and associations withA. castellaniienhanced survival ofYersiniaunder nutrient-rich conditions at 25°C and under nutrient-poor conditions at 37°C. Amoebae cultivated in the supernatant of oneYersiniastrain showed temperature- and time-dependent permeabilization. Intraprotozoan survival ofY. enterocoliticadepended on nutrient availability and temperature, with up to 2.8 log CFU/ml bacteria displaying intracellular survival at 7°C for at least 4 days in nutrient-rich medium. Transmission electron microscopy was performed to locate theYersiniacells inside the amoebae. AsYersiniaandAcanthamoebashare similar ecological niches, this interaction identifies a role of free-living protozoa in the ecology and epidemiology ofY. enterocolitica.

scholarly journals Fast and Sensitive Detection of Bacillus anthracis Spores by Immunoassay

2012 ◽  
Vol 78 (18) ◽  
pp. 6491-6498 ◽  
Author(s):  
Nathalie Morel ◽  
Hervé Volland ◽  
Julie Dano ◽  
Patricia Lamourette ◽  
Patricia Sylvestre ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Electrical Current ◽  
Biological Weapons ◽  
Meso Scale Discovery ◽  
Simple Method ◽  
Content Type ◽  
Bacillus Anthracis Spores ◽  
Luminescent Signal ◽  
Sample Purification ◽  
Phosphate Buffered Saline

ABSTRACTBacillus anthracisis one of the most dangerous potential biological weapons, and it is essential to develop a rapid and simple method to detectB. anthracisspores in environmental samples. The immunoassay is a rapid and easy-to-use method for the detection ofB. anthracisby means of antibodies directed against surface spore antigens. With this objective in view, we have produced a panel of monoclonal antibodies againstB. anthracisand developed colorimetric and electrochemiluminescence (ECL) immunoassays. Using Meso Scale Discovery ECL technology, which is based on electrochemiluminescence (ECL) detection utilizing a sulfo-Tag label that emits light upon electrochemical stimulation (using a dedicated ECL plate reader, an electrical current is placed across the microplate with electrodes integrated into the bottom of the plate, resulting in a series of electrically induced reactions leading to a luminescent signal), a detection limit ranging between 0.3 × 103and 103CFU/ml (i.e., 30 to 100 spores per test), depending on theB. anthracisstrain assayed, was achieved. In complex matrices (5 mg/ml of soil or simulated powder), the detection level (without any sample purification or concentration) was never altered more than 3-fold compared with the results obtained in phosphate-buffered saline.

scholarly journals Evaluation of the Efficacy of Methyl Bromide in the Decontamination of Building and Interior Materials Contaminated with Bacillus anthracis Spores

2016 ◽  
Vol 82 (7) ◽  
pp. 2003-2011 ◽  
Author(s):  
Joseph P. Wood ◽  
Morgan Wendling ◽  
William Richter ◽  
Andrew Lastivka ◽  
Leroy Mickelsen
Keyword(s):  
Bacillus Anthracis ◽  
Methyl Bromide ◽  
Contact Time ◽  
Geobacillus Stearothermophilus ◽  
Efficacy Data ◽  
Content Type ◽  
New Information ◽  
Bacillus Anthracis Spores ◽  
Effective Use ◽  
Selection Of

ABSTRACTThe primary goal of this study was to determine the conditions required for the effective inactivation ofBacillus anthracisspores on materials by using methyl bromide (MeBr) gas. Another objective was to obtain comparative decontamination efficacy data with three avirulent microorganisms to assess their potential for use as surrogates forB. anthracisAmes. Decontamination tests were conducted with spores ofB. anthracisAmes andGeobacillus stearothermophilus,B. anthracisNNR1Δ1, andB. anthracisSterne inoculated onto six different materials. Experimental variables included temperature, relative humidity (RH), MeBr concentration, and contact time. MeBr was found to be an effective decontaminant under a number of conditions. This study highlights the important role that RH has when fumigation is performed with MeBr. There were no tests in which a ≥6-log10reduction (LR) ofB. anthracisAmes was achieved on all materials when fumigation was done at 45% RH. At 75% RH, an increase in the temperature, the MeBr concentration, or contact time generally improved the efficacy of fumigation with MeBr. This study provides new information for the effective use of MeBr at temperatures and RH levels lower than those that have been recommended previously. The study also provides data to assist with the selection of an avirulent surrogate forB. anthracisAmes spores when additional tests with MeBr are conducted.

scholarly journals Adaptation in a Fibronectin Binding Autolysin of Staphylococcus saprophyticus

mSphere ◽  
2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Tatum D. Mortimer ◽  
Douglas S. Annis ◽  
Mary B. O’Neill ◽  
Lindsey L. Bohr ◽  
Tracy M. Smith ◽  
...  
Keyword(s):  
Public Health ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Pathogenic Bacteria ◽  
Human Microbiome ◽  
Invasive Disease ◽  
Human Infection ◽  
Content Type ◽  
Staphylococcus Saprophyticus ◽  
Tract Infections

ABSTRACT Staphylococcus saprophyticus is an important cause of urinary tract infections (UTI) in women; such UTI are common, can be severe, and are associated with significant impacts to public health. In addition to being a cause of human UTI, S. saprophyticus can be found in the environment, in food, and associated with animals. After discovering that UTI strains of S. saprophyticus are for the most part closely related to each other, we sought to determine whether these strains are specially adapted to cause disease in humans. We found evidence suggesting that a mutation in the gene aas is advantageous in the context of human infection. We hypothesize that the mutation allows S. saprophyticus to survive better in the human urinary tract. These results show how bacteria found in the environment can evolve to cause disease. Human-pathogenic bacteria are found in a variety of niches, including free-living, zoonotic, and microbiome environments. Identifying bacterial adaptations that enable invasive disease is an important means of gaining insight into the molecular basis of pathogenesis and understanding pathogen emergence. Staphylococcus saprophyticus, a leading cause of urinary tract infections, can be found in the environment, food, animals, and the human microbiome. We identified a selective sweep in the gene encoding the Aas adhesin, a key virulence factor that binds host fibronectin. We hypothesize that the mutation under selection (aas_2206A>C) facilitates colonization of the urinary tract, an environment where bacteria are subject to strong shearing forces. The mutation appears to have enabled emergence and expansion of a human-pathogenic lineage of S. saprophyticus. These results demonstrate the power of evolutionary genomic approaches in discovering the genetic basis of virulence and emphasize the pleiotropy and adaptability of bacteria occupying diverse niches. IMPORTANCE Staphylococcus saprophyticus is an important cause of urinary tract infections (UTI) in women; such UTI are common, can be severe, and are associated with significant impacts to public health. In addition to being a cause of human UTI, S. saprophyticus can be found in the environment, in food, and associated with animals. After discovering that UTI strains of S. saprophyticus are for the most part closely related to each other, we sought to determine whether these strains are specially adapted to cause disease in humans. We found evidence suggesting that a mutation in the gene aas is advantageous in the context of human infection. We hypothesize that the mutation allows S. saprophyticus to survive better in the human urinary tract. These results show how bacteria found in the environment can evolve to cause disease.

scholarly journals Revisiting the Concept of Targeting Only Bacillus anthracis Toxins as a Treatment for Anthrax

2016 ◽  
Vol 60 (8) ◽  
pp. 4878-4885 ◽  
Author(s):  
Itai Glinert ◽  
Elad Bar-David ◽  
Assa Sittner ◽  
Shay Weiss ◽  
Josef Schlomovitz ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Protein Fraction ◽  
Neutralizing Antibodies ◽  
Pathogenic Bacteria ◽  
Protective Antigen ◽  
Lethal Factor ◽  
Immunofluorescence Assay ◽  
Secreted Protein ◽  
Content Type

ABSTRACTProtective antigen (PA)-based vaccines are effective in preventing the development of fatal anthrax disease both in humans and in relevant animal models. TheBacillus anthracistoxins lethal toxin (lethal factor [LF] plus PA) and edema toxin (edema factor [EF] plus PA) are essential for the establishment of the infection, as inactivation of these toxins results in attenuation of the pathogen. Since the toxins reach high toxemia levels at the bacteremic stages of the disease, the CDC's recommendations include combining antibiotic treatment with antitoxin (anti-PA) immunotherapy. We demonstrate here that while treatment with a highly potent neutralizing monoclonal antibody was highly efficient as postexposure prophylaxis treatment, it failed to protect rabbits with any detectable bacteremia (≥10 CFU/ml). In addition, we show that while PA vaccination was effective against a subcutaneous spore challenge, it failed to protect rabbits against systemic challenges (intravenous injection of vegetative bacteria) with the wild-type Vollum strain or a toxin-deficient mutant. To test the possibility that additional proteins, which are secreted by the bacteria under pathogenicity-stimulating conditionsin vitro, may contribute to the vaccine's potency, we immunized rabbits with a secreted protein fraction from a toxin-null mutant. The antiserum raised against the secreted fraction reacts with the bacteria in an immunofluorescence assay. Immunization with the secreted protein fraction did not protect the rabbits against a systemic challenge with the fully pathogenic bacteria. Full protection was obtained only by a combined vaccination with PA and the secreted protein fraction. Therefore, these results indicate that an effective antiserum treatment in advanced stages of anthrax must include toxin-neutralizing antibodies in combination with antibodies against bacterial cell targets.

scholarly journals The Papain Inhibitor (SPI) of Streptomyces mobaraensis Inhibits Bacterial Cysteine Proteases and Is an Antagonist of Bacterial Growth

2013 ◽  
Vol 57 (7) ◽  
pp. 3388-3391 ◽  
Author(s):  
Stephan Zindel ◽  
Wendy E. Kaman ◽  
Sabrina Fröls ◽  
Felicitas Pfeifer ◽  
Anna Peters ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacillus Anthracis ◽  
Pathogenic Bacteria ◽  
Cysteine Proteases ◽  
Inhibitory Effect ◽  
Inhibitory Protein ◽  
Content Type ◽  
Cysteine Protease Activity ◽  
Streptomyces Mobaraensis ◽  
Culture Supernatants

ABSTRACTA novel papain inhibitory protein (SPI) fromStreptomyces mobaraensiswas studied to measure its inhibitory effect on bacterial cysteine protease activity (Staphylococcus aureusSspB) and culture supernatants (Porphyromonas gingivalis,Bacillus anthracis). Further, growth ofBacillus anthracis,Staphylococcus aureus,Pseudomonas aeruginosa, andVibrio choleraewas completely inhibited by 10 μM SPI. At this concentration of SPI, no cytotoxicity was observed. We conclude that SPI inhibits bacterial virulence factors and has the potential to become a novel therapeutic treatment against a range of unrelated pathogenic bacteria.

scholarly journals Existence of Separate Domains in Lysin PlyG for Recognizing Bacillus anthracis Spores and Vegetative Cells

2012 ◽  
Vol 56 (10) ◽  
pp. 5031-5039 ◽  
Author(s):  
Hang Yang ◽  
Dian-Bing Wang ◽  
Qiuhua Dong ◽  
Zhiping Zhang ◽  
Zongqiang Cui ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Catalytic Domain ◽  
Vegetative Cells ◽  
Content Type ◽  
Bacillus Anthracis Spores ◽  
Acid Domain ◽  
New Biomarkers ◽  
First Time ◽  
Amino Acid Domain ◽  
Spore Forming Bacteria

ABSTRACTAs a potential antimicrobial, the bacteriophage lysin PlyG has been reported to specifically recognizeBacillus anthracisvegetative cells only and to killB. anthracisvegetative cells and its germinating spores. However, how PlyG interacts withB. anthracisspores remains unclear. Herein, a 60-amino-acid domain in PlyG (residues 106 to 165), located mainly in the previously identified catalytic domain, was found able to specifically recognizeB. anthracisspores but not vegetative cells. The exosporium of the spores was found to be the most probable binding target of this domain. This is the first time that a lysin for spore-forming bacteria has been found to have separate domains to recognize spores and vegetative cells, which might help in understanding the coevolution of phages with spore-forming bacteria. Besides providing new biomarkers for developing better assays for identifyingB. anthracisspores, the newly found domain may be helpful in developing PlyG as a preventive antibiotic to reduce the threat of anthrax in suspected exposures toB. anthracisspores.

scholarly journals A Bacteriophage T4 Nanoparticle-Based Dual Vaccine against Anthrax and Plague

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Pan Tao ◽  
Marthandan Mahalingam ◽  
Jingen Zhu ◽  
Mahtab Moayeri ◽  
Jian Sha ◽  
...  
Keyword(s):  
Immune Responses ◽  
Bacillus Anthracis ◽  
Yersinia Pestis ◽  
Pathogenic Bacteria ◽  
Bacteriophage T4 ◽  
The United States ◽  
Complete Protection ◽  
Pneumonic Plague ◽  
Content Type ◽  
Phage T4

ABSTRACT Bacillus anthracis and Yersinia pestis, the causative agents of anthrax and plague, respectively, are two of the deadliest pathogenic bacteria that have been used as biological warfare agents. Although Biothrax is a licensed vaccine against anthrax, no Food and Drug Administration-approved vaccine exists for plague. Here, we report the development of a dual anthrax-plague nanoparticle vaccine employing bacteriophage (phage) T4 as a platform. Using an in vitro assembly system, the 120- by 86-nm heads (capsids) of phage T4 were arrayed with anthrax and plague antigens fused to the small outer capsid protein Soc (9 kDa). The antigens included the anthrax protective antigen (PA) (83 kDa) and the mutated (mut) capsular antigen F1 and the low-calcium-response V antigen of the type 3 secretion system from Y. pestis (F1mutV) (56 kDa). These viral nanoparticles elicited robust anthrax- and plague-specific immune responses and provided complete protection against inhalational anthrax and/or pneumonic plague in three animal challenge models, namely, mice, rats, and rabbits. Protection was demonstrated even when the animals were simultaneously challenged with lethal doses of both anthrax lethal toxin and Y. pestis CO92 bacteria. Unlike the traditional subunit vaccines, the phage T4 vaccine uses a highly stable nanoparticle scaffold, provides multivalency, requires no adjuvant, and elicits broad T-helper 1 and 2 immune responses that are essential for complete clearance of bacteria during infection. Therefore, phage T4 is a unique nanoparticle platform to formulate multivalent vaccines against high-risk pathogens for national preparedness against potential bioterror attacks and emerging infections. IMPORTANCE Following the deadly anthrax attacks of 2001, the Centers for Disease Control and Prevention (CDC) determined that Bacillus anthracis and Yersinia pestis that cause anthrax and plague, respectively, are two Tier 1 select agents that pose the greatest threat to the national security of the United States. Both cause rapid death, in 3 to 6 days, of exposed individuals. We engineered a virus nanoparticle vaccine using bacteriophage T4 by incorporating key antigens of both B. anthracis and Y. pestis into one formulation. Two doses of this vaccine provided complete protection against both inhalational anthrax and pneumonic plague in animal models. This dual anthrax-plague vaccine is a strong candidate for stockpiling against a potential bioterror attack involving either one or both of these biothreat agents. Further, our results establish the T4 nanoparticle as a novel platform to develop multivalent vaccines against pathogens of high public health significance.

scholarly journals Microbicidal Power of Alpha Radiation in Sterilizing Germinating Bacillus anthracis Spores

2013 ◽  
Vol 58 (3) ◽  
pp. 1813-1815 ◽  
Author(s):  
Johanna Rivera ◽  
Alfred Morgenstern ◽  
Frank Bruchertseifer ◽  
John F. Kearney ◽  
Charles L. Turnbough ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Dependent Manner ◽  
Alpha Radiation ◽  
Content Type ◽  
Immunodominant Antigen ◽  
Spore Killing ◽  
Bacillus Anthracis Spores ◽  
A Site ◽  
Antigen Antibody ◽  
Dose Dependent

ABSTRACTRadioimmunotherapy (RIT) takes advantage of the specificity and affinity of the antigen-antibody interaction to deliver microbicidal radioactive nuclides to a site of infection. In this study, we investigated the microbicidal properties of an alpha particle-emitting213Bi-labeled monoclonal antibody (MAb), EA2-1 (213Bi-EA2-1), that binds to the immunodominant antigen onBacillus anthracisspores. Our results showed that dormant spores were resistant to213Bi-EA2-1. Significant spore killing was observed following treatment with EA2-1 labeled with 300 μCi213Bi; however, this effect was not dependent on the MAb. In contrast, when spores were germinating,213Bi-EA2-1 mediated MAb-specific killing in a dose-dependent manner. Dormant spores are very resistant to RIT, and RIT should focus on targeting vegetative cells and germinating spores.

scholarly journals Nanomechanical Characterization of Bacillus anthracis Spores by Atomic Force Microscopy

2016 ◽  
Vol 82 (10) ◽  
pp. 2988-2999 ◽  
Author(s):  
Alex G. Li ◽  
Larry W. Burggraf ◽  
Yun Xing
Keyword(s):  
Atomic Force Microscopy ◽  
Bacillus Anthracis ◽  
Elevated Temperatures ◽  
Adhesion Force ◽  
Spore Surface ◽  
Content Type ◽  
Force Microscopy ◽  
Nanomechanical Properties ◽  
Atomic Force ◽  
Bacillus Anthracis Spores

ABSTRACTThe study of structures and properties of bacterial spores is important to understanding spore formation and biological responses to environmental stresses. While significant progress has been made over the years in elucidating the multilayer architecture of spores, the mechanical properties of the spore interior are not known. Here, we present a thermal atomic force microscopy (AFM) study of the nanomechanical properties of internal structures ofBacillus anthracisspores. We developed a nanosurgical sectioning method in which a stiff diamond AFM tip was used to cut an individual spore, exposing its internal structure, and a soft AFM tip was used to image and characterize the spore interior on the nanometer scale. We observed that the elastic modulus and adhesion force, including their thermal responses at elevated temperatures, varied significantly in different regions of the spore section. Our AFM images indicated that the peptidoglycan (PG) cortex ofBacillus anthracisspores consisted of rod-like nanometer-sized structures that are oriented in the direction perpendicular to the spore surface. Our findings may shed light on the spore architecture and properties.IMPORTANCEA nanosurgical AFM method was developed that can be used to probe the structure and properties of the spore interior. The previously unknown ultrastructure of the PG cortex ofBacillus anthracisspores was observed to consist of nanometer-sized rod-like structures that are oriented in the direction perpendicular to the spore surface. The variations in the nanomechanical properties of the spore section were largely correlated with its chemical composition. Different components of the spore materials showed different thermal responses at elevated temperatures.

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