Microevolution during an Anthrax outbreak leading to clonal heterogeneity and penicillin resistance

Anthrax is a bacterial disease primarily affecting grazing animals but it can also cause severe disease in humans. We have used genomic epidemiology to study microevolution of the bacterium in a confined outbreak in cattle which involved emergence of an antibiotic-resistant phenotype. At the time of death, the animals contained a heterogeneous population of Single Nucleotide Variants (SNVs), some being clonal but most being subclonal. We found that independent isolates from the same carcass had similar levels of SNV differences as isolates from different animals. Furthermore the relative levels of subclonal populations were different in different locations in the same carcass. The heterogeneity appeared to be derived in part from heterogeneity in the infectious dose. The resistance phenotype was linked to clonal mutations in an anti-sigma factor gene and in one case was preceded by an acquisition of a hypermutator phenotype. In another animal, small subclonal populations were observed with counteracting mutations that had turned off the resistance genes. In summary, this study shows the importance of accounting for both acquired and inherited heterogeneity when doing high-resolution infection tracing and when estimating the risks associated with penicillin treatment.

Exoproteome analysis of a novel strain of Bacillus cereus implicated in disease resembling cutaneous anthrax

Bacillus cereus belongs to B. cereus sensu lato group, shared by six other related species including Bacillus anthracis. B. anthracis is the causative agent for serious illness affecting a wide range of animals as well as humans and is a category A Biological and Toxin Warfare (BTW) agent. Recent studies indicate that a Bacillus species other than B. anthracis can cause anthrax-like disease and role of anthrax virulence plasmids (pXO1 and pXO2) on the pathogenicity of B. cereus has been documented. B. cereus strain TF5 was isolated from the tissue fluid of cutaneous anthrax-like skin lesions of a human patient from an anthrax endemic area in India. The strain harboured a PA gene, however, presence of pXO1 or pXO2-like plasmids could not be ascertained using reported primers. Abundant exoproteome of the strain in the early stationary phase was elucidated using a 2-DE MS approach and compared with that from a reference B. cereus strain. Analysis of proteins showing qualitative and quantitative differences between the two strains indicated an altered regulatory mechanism and putative role of S-layer protein and sphingomyelinase in the pathogenesis of strain TF5. Phylogenetic analysis of the S-layer protein indicated close affiliation of the strain with anthracis-like B. cereus strains such as B. cereus var. anthracis strain CI; whereas sphingomyelinase exhibited specific relationship with all the strains of B. anthracis apart from that with anthracis-like B. cereus strains.

Retrospective review of the case of cutaneous anthrax-malignant pustule from 1995 in 15-year old girl

A 15-year-old girl was admitted to our Department with cutaneous lesion resembling black eschar. Anamnesis revealed that before getting ill she was wearing pullover made of rough sheep's wool and ornaments made of leather like straps. Cutaneous anthrax was confirmed by identification of B. anthracis in specimens from weeping ulceration, culture from black eschar, thermoprecipitation test, and bioassay on guinea pig. The girl was treated with crystalline Penicillin. She responded well to the therapy and recovered after 28 days. What attracts attention in presented case is the fact that the girl didn't belong to high risk group of human anthrax, which might lead to misdiagnosis. In 1990-1999, Poland there were reported 22 cases of anthrax - it was almost exclusively cutaneous form. In the years following 1999 antrax was reported even less often - in the period 1991-2013 it was recorded a total of 26 cutaneous anthrax cases.

Screening for anthrax occurrence in soil of flooded rural areas in Poland after rainfalls in spring 2010

INTRODUCTION AND OBJECTIVE

Anthrax spores remain viable and infectious in soil for decades. Flood water can percolate towards the surface the spores buried in soil. Moreover, the flood water might transport spores to areas previously unaffected. After the water recedes the spores located on the surface of the ground can be consumed by grazing animals and cause outbreaks of anthrax.

MATERIALS AND METHOD

Soil samples were collected in areas of Poland most affected by floods in 2010 (Lubelskie, Świętokrzyskie, Podkarpackie and Mazowieckie provinces). After heating with the aim to kill vegetative forms of bacteria, the samples were cultured on PLET agar and the resulted colonies were investigated in terms of motility and presence of anthrax specific chromosomal (SG-749, plcR) and plasmid markers (capB, pagA).

RESULTS

In total, 424 spore-forming, aerobically growing isolates were collected from the tested soil samples. Eighty-nine of them were non-motile. All the isolates were negative in PCR for anthrax specific chromosomal and plasmid markers.

CONCLUSIONS

Spores of B. anthracis that could be related to risk of anthrax outbreaks were not detected in soil samples tested in this study. The negative results presented may not be proof that Poland is country free of anthrax. The results, however, may suggest a relatively low risk of anthrax outbreaks being triggered in the sampled areas.

Sensitive and Rapid Quantitative Detection of Anthrax Spores Isolated from Soil Samples by Real-Time PCR

Quantitative analysis of anthrax spores from environmental samples is essential for accurate detection and risk assessment since Bacillus anthracis spores have been shown to be one of the most effective biological weapons. Using TaqMan real-time PCR, specific primers and probes were designed for the identification of pathogenic B. anthracis strains from pag gene and cap gene on two plasmids, pXO1 and pXO2, as well as a sap gene encoded on the S-layer. To select the appropriate lysis method of anthrax spore from environmental samples, several heat treatments and germination methods were evaluated with multiplex-PCR. Among them, heat treatment of samples suspended with sucrose plus non-ionic detergent was considered an effective spore disruption method because it detected up to 10(5) spores/g soil by multiplex-PCR. Serial dilutions of B. anthracis DNA and spore were detected up to a level of 0.1 ng/ microliters and 10 spores/ml, respectively, at the correlation coefficient of 0.99 by real-time PCR. Quantitative analysis of anthrax spore could be obtained from the comparison between C(T) value and serial dilutions of soil sample at the correlation coefficient of 0.99. Additionally, spores added to soil samples were detected up to 10(4) spores/g soil within 3 hr by real-time PCR. As a consequence, we established a rapid and accurate detection system for environmental anthrax spores using real-time PCR, avoiding time and labor-consuming preparation steps such as enrichment culturing and DNA preparation.

Sensitive Detection ofBacillus anthracisUsing a Binding Protein Originating from γ-Phage

Detection of biological weapons is a primary concern in force protection, treaty verification, and safeguarding civilian populations against domestic terrorism. One great concern is the detection of Bacillus anthracis, the causative agent of anthrax. Therefore, there is a pressing need to develop novel methods for rapid, simple, and precise detection of B. anthracis. Here, we report that the C-terminal region of gamma-phage lysin protein (PlyG) binds specifically to the cell wall of B. anthracis and the recombinant protein corresponding to this region (positions, 156-233), PlyGB, is available as a bioprobe for detection of B. anthracis. Our detection method, based on a membrane direct blot assay using recombinant PlyGB, was more rapid and sensitive than the gamma-phage test and was simpler and more inexpensive than genetic methods such as PCR, or immunological methods using specific antibodies. Furthermore, its specificity was comparable to the gamma-phage test. PlyGB is applicable in conventional methods instead of antibodies and could be a potent tool for detection of B. anthracis.

Detection of Bacillus anthracis DNA in complex soil and air samples using next-generation sequencing

Bacillus anthracis is the potentially lethal etiologic agent of anthrax disease, and is a significant concern in the realm of biodefense. One of the cornerstones of an effective biodefense strategy is the ability to detect infectious agents with a high degree of sensitivity and specificity in the context of a complex sample background. The nature of the B. anthracis genome, however, renders specific detection difficult, due to close homology with B. cereus and B. thuringiensis. We therefore elected to determine the efficacy of next-generation sequencing analysis and microarrays for detection of B. anthracis in an environmental background. We applied next-generation sequencing to titrated genome copy numbers of B. anthracis in the presence of background nucleic acid extracted from aerosol and soil samples. We found next-generation sequencing to be capable of detecting as few as 10 genomic equivalents of B. anthracis DNA per nanogram of background nucleic acid. Detection was accomplished by mapping reads to either a defined subset of reference genomes or to the full GenBank database. Moreover, sequence data obtained from B. anthracis could be reliably distinguished from sequence data mapping to either B. cereus or B. thuringiensis. We also demonstrated the efficacy of a microbial census microarray in detecting B. anthracis in the same samples, representing a cost-effective and high-throughput approach, complementary to next-generation sequencing. Our results, in combination with the capacity of sequencing for providing insights into the genomic characteristics of complex and novel organisms, suggest that these platforms should be considered important components of a biosurveillance strategy.

Evidence of local persistence of human anthrax in the country of georgia associated with environmental and anthropogenic factors

BACKGROUND

Anthrax is a soil-borne disease caused by the bacterium Bacillus anthracis and is considered a neglected zoonosis. In the country of Georgia, recent reports have indicated an increase in the incidence of human anthrax. Identifying sub-national areas of increased risk may help direct appropriate public health control measures. The purpose of this study was to evaluate the spatial distribution of human anthrax and identify environmental/anthropogenic factors associated with persistent clusters.

METHODS/FINDINGS

A database of human cutaneous anthrax in Georgia during the period 2000-2009 was constructed using a geographic information system (GIS) with case data recorded to the community location. The spatial scan statistic was used to identify persistence of human cutaneous anthrax. Risk factors related to clusters of persistence were modeled using a multivariate logistic regression. Areas of persistence were identified in the southeastern part of the country. Results indicated that the persistence of human cutaneous anthrax showed a strong positive association with soil pH and urban areas.

CONCLUSIONS/SIGNIFICANCE

Anthrax represents a persistent threat to public and veterinary health in Georgia. The findings here showed that the local level heterogeneity in the persistence of human cutaneous anthrax necessitates directed interventions to mitigate the disease. High risk areas identified in this study can be targeted for public health control measures such as farmer education and livestock vaccination campaigns.

Erythropoiesis suppression is associated with anthrax lethal toxin-mediated pathogenic progression

Anthrax is a disease caused by the bacterium Bacillus anthracis, which results in high mortality in animals and humans. Although some of the mechanisms are already known such as asphyxia, extensive knowledge of molecular pathogenesis of this disease is deficient and remains to be further investigated. Lethal toxin (LT) is a major virulence factor of B. anthracis and a specific inhibitor/protease of mitogen-activated protein kinase kinases (MAPKKs). Anthrax LT causes lethality and induces certain anthrax-like symptoms, such as anemia and hypoxia, in experimental mice. Mitogen-activated protein kinases (MAPKs) are the downstream pathways of MAPKKs, and are important for erythropoiesis. This prompted us to hypothesize that anemia and hypoxia may in part be exacerbated by erythropoietic dysfunction. As revealed by colony-forming cell assays in this study, LT challenges significantly reduced mouse erythroid progenitor cells. In addition, in a proteolytic activity-dependent manner, LT suppressed cell survival and differentiation of cord blood CD34⁺-derived erythroblasts in vitro. Suppression of cell numbers and the percentage of erythroblasts in the bone marrow were detected in LT-challenged C57BL/6J mice. In contrast, erythropoiesis was provoked through treatments of erythropoietin, significantly ameliorating the anemia and reducing the mortality of LT-treated mice. These data suggested that suppressed erythropoiesis is part of the pathophysiology of LT-mediated intoxication. Because specific treatments to overcome LT-mediated pathogenesis are still lacking, these efforts may help the development of effective treatments against anthrax.

Quantitative models of the dose-response and time course of inhalational anthrax in humans

Anthrax poses a community health risk due to accidental or intentional aerosol release. Reliable quantitative dose-response analyses are required to estimate the magnitude and timeline of potential consequences and the effect of public health intervention strategies under specific scenarios. Analyses of available data from exposures and infections of humans and non-human primates are often contradictory. We review existing quantitative inhalational anthrax dose-response models in light of criteria we propose for a model to be useful and defensible. To satisfy these criteria, we extend an existing mechanistic competing-risks model to create a novel Exposure–Infection–Symptomatic illness–Death (EISD) model and use experimental non-human primate data and human epidemiological data to optimize parameter values. The best fit to these data leads to estimates of a dose leading to infection in 50% of susceptible humans (ID₅₀) of 11,000 spores (95% confidence interval 7,200–17,000), ID₁₀ of 1,700 (1,100–2,600), and ID₁ of 160 (100–250). These estimates suggest that use of a threshold to human infection of 600 spores (as suggested in the literature) underestimates the infectivity of low doses, while an existing estimate of a 1% infection rate for a single spore overestimates low dose infectivity. We estimate the median time from exposure to onset of symptoms (incubation period) among untreated cases to be 9.9 days (7.7–13.1) for exposure to ID₅₀, 11.8 days (9.5–15.0) for ID₁₀, and 12.1 days (9.9–15.3) for ID₁. Our model is the first to provide incubation period estimates that are independently consistent with data from the largest known human outbreak. This model refines previous estimates of the distribution of early onset cases after a release and provides support for the recommended 60-day course of prophylactic antibiotic treatment for individuals exposed to low doses.

Anthrax poses a potential community health risk due to accidental or intentional aerosol release. We address the need for a transparent and defensible quantitative dose-response model for inhalational anthrax that is useful for risk assessors in estimating the magnitude and timeline of potential public health consequences should a release occur. Our synthesis of relevant data and previous modeling efforts identifies areas of improvement among many commonly cited dose-response models and estimates. To address those deficiencies, we provide a new model that is based on clear, transparent assumptions and published data from human and non-human primate exposures. Our resulting estimates provide important insight into the infectivity to humans of low inhaled doses of anthrax spores and the timeline of infections after an exposure event. These insights are critical to assessment of the impacts of delays in responding to a large scale aerosol release, as well as the recommended course of antibiotic administration to those potentially exposed.

Detection of biological warfare agents using ultra violet-laser induced fluorescence LIDAR

This review has been written to highlight the threat of biological warfare agents, their types and detection. Bacterial biological agent Bacillus anthracis (bacteria causing the disease anthrax) which is most likely to be employed in biological warfare is being discussed in detail. Standoff detection of biological warfare agents in aerosol form using Ultra violet-Laser Induced Fluorescence (UV-LIF) spectroscopy method has been studied. Range-resolved detection and identification of biological aerosols by both nano-second and non-linear femto-second LIDAR is also discussed. Calculated received fluorescence signal for a cloud of typical biological agent Bacillus globigii (Simulants of B. anthracis) at a location of ~5.0 km at different concentrations in presence of solar background radiation has been described. Overview of current research efforts in internationally available working UV-LIF LIDAR systems are also mentioned briefly.

Anthrax among heroin users in Europe possibly caused by same Bacillus anthracis strain since 2000

Injection anthrax was described first in 2000 in a heroin-injecting drug user in Norway. New anthrax cases among heroin consumers were detected in the United Kingdom (52 cases) and Germany (3 cases) in 2009-10. In June 2012, a fatal case occurred in Regensburg, Bavaria. As of December 2012, 13 cases had been reported in this new outbreak from Germany, Denmark, France and the United Kingdom. We analysed isolates from 2009-10 and 2012 as well as from the first injection anthrax case in Norway in 2000 by comparative molecular typing using a high resolution 31 marker multilocus variable-number tandem repeat analysis (MLVA) and a broad single nucleotide polymorphism (SNP) analysis. Our results show that all cases may be traced back to the same outbreak strain. They also indicate the probability of a single source contaminating heroin and that the outbreak could have lasted for at least a decade. However, an additional serological pilot study in two German regions conducted in 2011 failed to discover additional anthrax cases among 288 heroin users.

Adenylate cyclases involvement in pathogenicity, a minireview

Cyclic AMP (cAMP), one of the most important secondary messengers, is produced by adenylate cyclase (AC) from adenosine triphosphate (ATP). AC is a widespread enzyme, being present both in prokaryotes and eukaryotes. Although they have the same enzymatic activity (ATP cyclization), the structure of these proteins varies, depending on their function and the producing organism. Some pathogenic bacteria utilize these enzymes as toxins which interact with calmodulin (or another eukaryote activator), causing intense cAMP synthesis and disruption of infected cell functions. In contrast, other pathogenic bacteria benefit of augmentation of AC activity for their own function. Based on sequence analysis ofAC catalytic domain from two pathogenic bacteria (Bacillus anthracis and Bordetellapertussis) with known three-dimensional structures, a possible secondary structure for 1-255 amino acid fragment from Pseudomonas aeruginosa AC (with 80TKGFSVKGKSS90 as the ATP binding site) is proposed.

Molecular epidemiologic investigation of an anthrax outbreak among heroin users, Europe

In December 2009, two unusual cases of anthrax were diagnosed in heroin users in Scotland. A subsequent anthrax outbreak in heroin users emerged throughout Scotland and expanded into England and Germany, sparking concern of nefarious introduction of anthrax spores into the heroin supply. To better understand the outbreak origin, we used established genetic signatures that provided insights about strain origin. Next, we sequenced the whole genome of a representative Bacillus anthracis strain from a heroin user (Ba4599), developed Ba4599-specific single-nucleotide polymorphism assays, and genotyped all available material from other heroin users with anthrax. Of 34 case-patients with B. anthracis-positive PCR results, all shared the Ba4599 single-nucleotide polymorphism genotype. Phylogeographic analysis demonstrated that Ba4599 was closely related to strains from Turkey and not to previously identified isolates from Scotland or Afghanistan, the presumed origin of the heroin. Our results suggest accidental contamination along the drug trafficking route through a cutting agent or animal hides used to smuggle heroin into Europe.

Achieving consistent multiple daily low-dose Bacillus anthracis spore inhalation exposures in the rabbit model

Repeated low-level exposures to biological agents could occur before or after the remediation of an environmental release. This is especially true for persistent agents such as B. anthracis spores, the causative agent of anthrax. Studies were conducted to examine aerosol methods needed for consistent daily low aerosol concentrations to deliver a low-dose (less than 10(6) colony forming units (CFU) of B. anthracis spores) and included a pilot feasibility characterization study, acute exposure study, and a multiple 15 day exposure study. This manuscript focuses on the state-of-the-science aerosol methodologies used to generate and aerosolize consistent daily low aerosol concentrations and resultant low inhalation doses to rabbits. The pilot feasibility characterization study determined that the aerosol system was consistent and capable of producing very low aerosol concentrations. In the acute, single day exposure experiment, targeted inhaled doses of 1 × 10(2), 1 × 10(3), 1 × 10(4), and 1 × 10(5) CFU were used. In the multiple daily exposure experiment, rabbits were exposed multiple days to targeted inhaled doses of 1 × 10(2), 1 × 10(3), and 1 × 10(4) CFU. In all studies, targeted inhaled doses remained consistent from rabbit-to-rabbit and day-to-day. The aerosol system produced aerosolized spores within the optimal mass median aerodynamic diameter particle size range to reach deep lung alveoli. Consistency of the inhaled dose was aided by monitoring and recording respiratory parameters during the exposure with real-time plethysmography. Overall, the presented results show that the animal aerosol system was stable and highly reproducible between different studies and over multiple exposure days.

[Recombinant expression, purification and adhesion function identify of Bacillus anthracis BslA(260 -652) protein]

OBJECTIVE

To obtain the recombinant BslA(260-652) protein of Bacillus anthracis and prepare its antibody for the adhesion activity studies.

METHODS

The fragment coding BslA(260-652) was cloned into pET28a(+) plasmid and induced to express recombinant protein in E. coli Rosetta (DE3) by Isopropyl beta-D-1-thiogalactopyranoside (IPTG). The expressed recombinant soluble protein was purified by a column packed with Ni Resin. Purified protein was used as the antigen to immunize BABL/c mice for three times to raise polyclonal antibody. The adhesion activity of BlsA(260-652) was detected by immunofluorescence experiments and bacterial adherence assays.

RESULTS

The purity of the purified soluble BslA(260-652) was about 87.4%. ELISA assay titer of antiserum from vaccinated mice reached 1:20000. Western blot showed the antiserum could specifically recognize endogenous BslA protein. The purified BslA(260-652) displayed a typical adhesion-like function. Either the anti-BslA serum or the BslA(260-652) protein could inhibit A16R's Hela adherence.

CONCLUSION

The recombinant BslA(260-652) protein was successfully obtained, which would lay the foundation for further research of the anthrax vaccine and the role of this S-layer protein in the pathogenesis of anthrax.

Debridement increases survival in a mouse model of subcutaneous anthrax

Anthrax is caused by infection with Bacillus anthracis, a spore-forming gram-positive bacterium. A major virulence factor for B. anthracis is an immunomodulatory tripartite exotoxin that has been reported to alter immune cell chemotaxis and activation. It has been proposed that B. anthracis infections initiate through entry of spores into the regional draining lymph nodes where they germinate, grow, and disseminate systemically via the efferent lymphatics. If this model holds true, it would be predicted that surgical removal of infected tissues, debridement, would have little effect on the systemic dissemination of bacteria. This model was tested through the development of a mouse debridement model. It was found that removal of the site of subcutaneous infection in the ear increased the likelihood of survival and reduced the quantity of spores in the draining cervical lymph nodes (cLN). At the time of debridement 12 hours post-injection measurable levels of exotoxins were present in the ear, cLN, and serum, yet leukocytes within the cLN were activated; countering the concept that exotoxins inhibit the early inflammatory response to promote bacterial growth. We conclude that the initial entry of spores into the draining lymph node of cutaneous infections alone is not sufficient to cause systemic disease and that debridement should be considered as an adjunct to antibiotic therapy.

Outbreak of cutaneous anthrax in a tribal village: a clinico-epidemiological study

BACKGROUND

Anthrax is a life-threatening infectious disease that normally affects animals, especially ruminants. It is caused by the bacteria Bacillus anthracis. The most common mode of infection is through the skin, which causes a painless sore that usually heals without treatment. If left untreated, cutaneous anthrax may progress in up to 20% of cases to septicaemia with potentially lethal outcome.

METHODOLOGY

We visited a small tribal village of the state of West Bengal, where an outbreak of cutaneous anthrax was suspected following slaughtering a dead bullock. The population at risk were subjected to detailed interrogation, thorough clinical examination and relevant investigations.

RESULTS

The mean age of our study population was 32.1 years, and 100% were male. The mean incubation period was three days. Most cases (81.8%) were exposed to the bacteria during butchering. The predominantly affected sites were fingers (54.5%), followed by forearms (18.2%), around elbows (18.2%) and arm (9.1%). All cases initially had painless papules, ulcers with vesicles; dissemination of the lesion was seen in 27.3% of patients. 9 patients (who were alive) underwent complete blood count, baseline biochemistry and chest X-ray. Smears were made from the cutaneous lesions for gram's stain in 5 patients. Wound swabs were also inoculated in nutrient broth and subcultured in blood agar media. FNAC from the enlarged axillary lymph node was done in 1 patient and blood was sent for aerobic culture in 2 individuals. Both the blood cultures were sterile. Smears made from the culture obtained from cutaneous lesion of one of the affected person revealed gram positive aerobic spore bearing non-motile bacilli in long chain with capsular halo suggesting Bacillus anthracis. In this outbreak, the attack rate was 7% and case fatality rate was 18%.

CONCLUSION

Cutaneous anthrax should be considered as a differential diagnosis in cases presenting with painless ulcers, vesicles or eschars with a recent history of exposure to animals or animal products. It is important to recognise the clinical aspects of this disease in routine practice since any delay in treatment may have fatal consequences, as observed in this study.

New aspects of the infection mechanisms of Bacillus anthracis

Articles concerning new aspects of B. anthracis mechanisms of infection were reviewed. It was found, that the hair follicle plays an important role in the spore germination process. The hair follicle represent an important portal of entry in the course of the cutaneous form of disease infections. After mouse exposition to aerosol of spores prepared from B. anthracis strains, an increase in the level of TNF-α cytokines was observed. The TNF-α cytokines were produced after intrusion into the host by the microorganism. This process may play a significant role in the induced migration of infected cells APCs (Antigen Presenting Cells) via chemotactic signals to the lymph nodes. It was explained that IgG, which binds to the spore surface, activates the adaptive immune system response. As a result, the release C3b opsonin from the spore surface, and mediating of C3 protein fragments of B. anthracis spores phagocytosis by human macrophages, was observed. The genes coding germination spores protein in mutant strains of B. anthracis MIGD was a crucial discovery. According to this, it could be assumed that the activity of B. anthracis spores germination process is dependent upon the sleB, cwlJ1 and cwlJ2 genes, which code the GSLEs lithic enzymes. It was also discovered that the specific antibody for PA20, which binds to the PA20 antigenic determinant, are able to block further PA83 proteolytic fission on the surface of cells. This process neutralized PA functions and weakened the activity of free PA20, which is produced during the PA83 enzyme fission process. Interaction between PA63 monomer and LF may be helpful in the PA63 oligomerization and grouping process, and the creation of LF/PA63 complexes may be a part of an alternative process of assembling the anthrax toxin on the surface of cells. It was found that actin-dependent endocytosis plays an important role in the PA heptamerisation process and leads to blocking the toxin activity. Chaperones, a protein derived from host cells, may be helpful in ATP and cytosolic factors translocation, and in this way increase the translocation of diphteria toxin A domein (DTA) and substrate of fusion protein LF(N)-DTA.

Characterization of genetic diversity of Bacillus anthracis in France by using high-resolution melting assays and multilocus variable-number tandem-repeat analysis

Using high-resolution melting (HRM) analysis, we developed a cost-effective method to genotype a set of 13 phylogenetically informative single-nucleotide polymorphisms (SNPs) within the genome of Bacillus anthracis. SNP discrimination assays were performed in monoplex or duplex and applied to 100 B. anthracis isolates collected in France from 1953 to 2009 and a few reference strains. HRM provided a reliable and cheap alternative to subtype B. anthracis into one of the 12 major sublineages or subgroups. All strains could be correctly positioned on the canonical SNP (canSNP) phylogenetic tree, except the divergent Pasteur vaccine strain ATCC 4229. We detected the cooccurrence of three canSNP subgroups in France. The dominant B.Br.CNEVA sublineage was found to be prevalent in the Alps, the Pyrenees, the Auvergne region, and the Saône-et-Loire department. Strains affiliated with the A.Br.008/009 subgroup were observed throughout most of the country. The minor A.Br.001/002 subgroup was restricted to northeastern France. Multiple-locus variable-number tandem-repeat analysis using 24 markers further resolved French strains into 60 unique profiles and identified some regional patterns. Diversity found within the A.Br.008/009 and B.Br.CNEVA subgroups suggests that these represent old, ecologically established clades in France. Phylogenetic relationships with strains from other parts of the world are discussed.

Two cases of infection with Bacillus anthracis, Romania, October 2011

A cluster of two confirmed cases of anthrax were reported in October 2011 from a small village with a population of 3,400 people, in south-eastern Romania.One was a fatal case of cutaneous and anthrax meningoencephalitis, while the other had cutaneous anthrax. Both cases had been exposed to one Bacillus anthracis-infected cow via consumption of its meat or being involved in its slaughter.

The effects of anthrax lethal toxin on host barrier function

The pathological actions of anthrax toxin require the activities of its edema factor (EF) and lethal factor (LF) enzyme components, which gain intracellular access via its receptor-binding component, protective antigen (PA). LF is a metalloproteinase with specificity for selected mitogen-activated protein kinase kinases (MKKs), but its activity is not directly lethal to many types of primary and transformed cells in vitro. Nevertheless, in vivo treatment of several animal species with the combination of LF and PA (termed lethal toxin or LT) leads to morbidity and mortality, suggesting that LT-dependent toxicity is mediated by cellular interactions between host cells. Decades of research have revealed that a central hallmark of this toxicity is the disruption of key cellular barriers required to maintain homeostasis. This review will focus on the current understanding of the effects of LT on barrier function, highlighting recent progress in establishing the molecular mechanisms underlying these effects.