Human Anthrax: Update of the Diagnosis and Treatment

A novel method of species-specific molecular target mining and accurate discrimination of Bacillus cereus sensu lato

Bacillus cereus, a member of the Bacillus cereus sensu lato (B. cereus s.l.), is widely distributed in nature and can contaminate a variety of foods, leading to foodborne illnesses and substantial losses in the food industry. Although culture-based methods remain the gold standard for identifying B. cereus due to their high sensitivity under specific conditions, they are often complex and labor-intensive to implement. Furthermore, the high genetic similarity among certain members of the B. cereus s.l. makes it challenging to identify species-specific molecular targets, hindering the rapid and accurate differentiation of these bacteria. In this study, we introduce a novel method, comparative analysis based on whole genome slices (CAWGS), combined with the Basic Local Alignment Search Tool (BLAST) for efficient molecular target mining. Using CAWGS-BLAST and pan-genome analysis, we successfully identified new molecular targets for B. cereus, Bacillus thuringiensis, emetic B. cereus, Bacillus anthracis, Bacillus mycoides, Bacillus weihenstephanensis, and Bacillus megaterium. Based on these newly discovered targets, we developed a PCR-CRISPR/Cas12a method for detecting B. cereus s.l. and related species. Our research not only provides a rapid and accurate approach for discriminating B. cereus s.l. and related species, but also offers a universal and valuable reference for detecting foodborne pathogens, especially those with highly similar phenotypic and genetic characteristics.

Natural Products Produced by the Species of Bacillus cereus Group: Recent Updates

Bacillus cereus group produces diverse antimicrobial compounds through different metabolic pathways, including amino acid-based compounds, sugar derivatives, volatile and miscellaneous compounds. These antimicrobial compounds exhibit antibacterial and antifungal activities against various plant pathogens, promoting plant growth and enhancing tolerance to abiotic stresses. They also exhibit nematicidal activities against plant nematodes and antagonistic effects against pathogens in aquatic animals, promoting growth and inducing immune responses. Moreover, B. cereus group bacteria play a significant role in bioremediation by breaking down or neutralizing environmental pollutants, such as plastics, petroleum products, heavy metals, and insecticides. They produce enzymes like laccases, lipases, proteases, and various oxidases, contributing to the degradation of these pollutants. In the food industry, they can cause food poisoning due to their production of enterotoxins. However, they are also utilized in various industrial applications, such as producing environmentally friendly bio-based materials, biofertilizers, and nanoparticles. Notably, B. cereus transforms selenite into selenium nanoparticles, which have health benefits, including cancer prevention. In summary, B. cereus group bacteria have diverse applications in agriculture, bioremediation, industry, and medicine, contributing to sustainable and eco-friendly solutions across multiple fields. In this review, we have revised B. cereus group and the characteristics of every species; we have also highlighted the more important compounds secreted by the species of B. cereus group and the applications of these compounds. The aim is to explain the available secondary metabolites to classify the species from this group, increasing the knowledge about taxonomy of this group.

From Spores to Suffering: Understanding the Role of Anthrax in Bioterrorism

INTRODUCTION

Anthrax, caused by the bacterium Bacillus anthracis, stands as a formidable threat with both natural and bioterrorism-related implications. Its ability to afflict a wide range of hosts, including humans and animals, coupled with its potential use as a bioweapon, underscores the critical importance of understanding and advancing our capabilities to combat this infectious disease. In this context, exploring futuristic approaches becomes imperative, as they hold the promise of not only addressing current challenges but also ushering in a new era in anthrax management. This review delves into strategies to mitigate the impact of anthrax on global health and security, envisioning a future where our arsenal against anthrax is characterized by precision and adaptability.

MATERIALS AND METHODS

This article highlights the significant potential of anthrax as a bioweapon, while also highlighting current knowledge and strategies developed against this deadly pathogen. We have performed an extensive research and literature review in concordance with the criteria outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A search strategy was conducted by using numerous keywords on various academic databases, yielding an initial set of 546 records along with 80 supplementary articles. The search included research papers, review papers, perspectives, clinical guidelines, and scientific blogs. The primary and secondary screening of the articles were conducted by 2 independent reviewers along with a third reviewer mitigating any discrepancies and biases encountered during the process. A set of inclusion and exclusion criteria were formulated, and a PICO framework was adapted based on which multiple records were analyzed and considered for the review.

RESULTS

In total, 53 articles were selected after completing a comprehensive systematic literature review. This review proposes novel approaches and scientific analysis of the complexities surrounding anthrax in the context of bioterrorism, highlighting the emerging technologies and strategies employed for bioterrorism mitigation.

CONCLUSIONS

The upcoming advancements in anthrax research will be based on cutting-edge technologies and innovative approaches that demonstrate great potential for prevention, detection, and treatment. These advancements may include the incorporation of synthetic biology techniques such as precise manipulation of biological components, nanoscale diagnostics, and Clustered regularly interspaced short palindromic repeats-based technologies, which could revolutionize our ability to combat anthrax on a molecular level. As these progressive methodologies continue to evolve, the integration of these technologies has the potential to redefine our strategies against anthrax, providing more accurate, personalized, and adaptable approaches to address the challenges posed by this infectious threat.

Case report: Clinical characteristics of anthrax meningoencephalitis: two cases diagnosed using metagenomic next-generation sequencing and literature review

Purpose

To explore the clinical features, diagnosis, treatment, and prognosis of anthrax meningoencephalitis.

Methods

The clinical data of two cases of anthrax meningoencephalitis were summarized and the relevant literature was reviewed.

Results

Both patients, who were farmers, had cutaneous lesions prior to the onset of meningoencephalitis. The clinical manifestations included fever (2/2), headache (2/2), stupor (2/2), meningeal signs (2/2), and lymph node enlargement (2/2). The CSF analysis showed erythrocytes, increased neutrophils, low glucose levels and high protein levels. CSF cytology revealed rod-shaped bacilli. Metagenomic next-generation sequencing of the CSF from both patients detected Bacillus anthracis. Additionally, cultures confirmed the presence of endogenous spores of macrobacteria. Brain imaging revealed subarachnoid hemorrhages and minimal cerebral edema. Despite aggressive antibiotic treatment, both patients died. Fifty-seven articles of the past 70 years were reviewed. There were 59 patients of anthrax meningoencephalitis in total, including 46 patients died. Stupor (42/46, 91.3% vs. 3/13, 46.2%, p = 0.001), agitation (15/46, 32.6% vs. 0/13, 0.0%, p = 0.043) and intracranial hemorrhage (37/46, 80.4% vs. 4/13, 30.8%, p = 0.002) were more common in the deceased group. Two types of bactericidal drugs or intrathecal injection drugs presented more often in the surviving group (10/13, 76.9% vs. 13/46, 28.3%, p = 0.001), whereas penicillin monotherapy presented more often in the deceased group (23/46, 50.0% vs. 2/13, 15.4%, p = 0.026).

Conclusion

Anthrax meningoencephalitis typically presents as a rapidly progressive bacterial meningoencephalitis. The occurrence of stupor, agitation and intracranial hemorrhage is possibly correlated with poor outcome. Two types of bactericidal drugs or intrathecal injection drugs are associated with better prognosis. Metagenomic next-generation sequencing can quickly and accurately detect B. anthracis in CSF.

Anthrax: Transmission, Pathogenesis, Prevention and Treatment

Bacillus anthracis is a deadly pathogen that under unfavourable conditions forms highly resistant spores which enable them to survive for a long period of time. Spores of B. anthracis are transmitted through the contaminated soil or animal products and enter to the host through the skin, lungs or oral route and can cause cutaneous, injection, inhalation and gastrointestinal anthrax, respectively. The disease is caused by the toxin which is produced by them once they germinate within the host cell. Anthrax toxin is the major virulence factor which has the ability to kill the host cell. The role of protein kinases and phosphatases of B. anthracis in toxin production and other virulence related properties have also been reported. There are two vaccines, BioThrax and CYFENDUSTM, which are approved by the FDA-USA to prevent anthrax disease. Recently, anthrax toxin has also been shown to be a potential candidate for cancer therapeutics. Through present review, we aim to provide insights into sporulation, transmission and pathogenesis of B. anthracis as well as the current state of its prevention, treatment, vaccines and possible therapeutic uses in cancer.

Negative Association of Gulf War Illness Symptomatology with Predicted Binding Affinity of Anthrax Vaccine Antigen to Human Leukocyte (HLA) Class II Molecules

BACKGROUND

Anthrax is a serious disease caused by Bacillus anthracis (B. anthracis) with a very high mortality when the spores of B. anthracis are inhaled (inhalational anthrax). Aerosolized B. anthracis spores can be used as a deadly bioweapon. Vaccination against anthrax is the only effective preventive measure and, hence, the anthrax vaccine was administered to United States (and other) troops during the 1990-91 Gulf War. However, the anthrax vaccine is not harmless, and the anthrax vaccination has been linked to the occurrence and severity of Gulf War Illness (GWI), a debilitating Chronic Multisymptom Illness (CMI). We hypothesized that this is partly due to the combination of two factors, namely (a) the cytotoxicity of the antigen (anthrax Protective Antigen, PA) contained in the vaccine, and (b) the Human Leukocyte Antigen (HLA) genotype of susceptible vaccinees, reducing their ability to make antibodies against the cytotoxic PA.

METHOD

Here, we tested this hypothesis by determining the association between severity of GWI symptoms in 458 GW veterans and the overall strength of the binding affinity of the PA epitopes to the specific six Human Leukocyte Antigen (HLA) Class II alleles carried by each individual (two of each of the HLA-II genes: DPB1, DQB1, DRB1), responsible for initiating the process of antibody production in otherwise immunocompetent individuals, estimated in silico.

RESULTS

We found that the severity of GWI symptomatology was negatively and significantly correlated with the strength of the predicted binding affinity of PA peptides to HLA-II molecules (r=-0.356, p<0.001); the stronger the overall binding affinity, the weaker the symptoms. Since the binding of a peptide to an HLA-II molecule is the first and necessary step in initiating the production of antibodies, the findings above support our hypothesis that the severity of GWI symptomatology is partly due to a lack of HLA-II protection.

CONCLUSIONS

Reduced HLA protection against the toxic anthrax vaccine may underlie GWI.

Anthrax meningoencephalitis: A case report

The present study describes the case of a patient with anthrax meningoencephalitis with the aim of providing a scientific basis for the control of this disease. The cerebrospinal fluid and blood of the patient were tested for genes and Bacillus anthracis was detected. The patient's meningitis was cured following treatment. Tracing the route of infection, anthrax was detected on the chopping board of the rural cattle and sheep butcher shop where the patient had purchased meat. In 2018, the patient complained of intermittent nasal discharge for 11 days after brain injury and came to the Second People's Hospital of Liaocheng (Linqing, China). Considering the existence of cerebrospinal fluid rhinorrhea, the patient's cerebrospinal fluid biochemistry was assessed and showed low sugar and high protein levels, resulting in a diagnosis of bacterial encephalitis. This encephalitis was considered to be related to bacterial retrograde infection after cerebrospinal fluid rhinorrhea. It is required to strengthen the training of medical personnel according to guidelines and laws and improve the level of early detection, reporting and diagnosis, as well as timely treatment at medical institutions. There is an urgent need to intensify the education of the population regarding the awareness and prevention of the disease. For individuals involved in the breeding, slaughtering and processing of livestock, multiple measures need to be taken to comprehensively intervene and to enhance occupational protection awareness and disease prevention capabilities.

In-depth exploration of cutaneous anthrax: clinical and pathological manifestations of a case report

Anthrax is an acute infectious disease caused by Bacillus anthracis, which can infect various animals and humans. Cutaneous anthrax primarily presents as infiltrative, edematous erythema, surface vesicles, hemorrhagic vesicles, and necrotic eschar; some patients may also experience systemic symptoms such as fever and leukocytosis. With economic development and improvements in public health conditions, naturally occurring cases of cutaneous anthrax have significantly decreased, leading to limited reports on the pathological manifestations of this disease. This article reports a case of a patient with cutaneous anthrax diagnosed and treated in our hospital, aiming to explore the laboratory examinations, imaging, pathological features, and clinical treatment methods of the disease. The goal is to enhance understanding of anthrax and increase vigilance in clinical practice to avoid misdiagnosis and missed diagnosis. The described diagnostic and therapeutic processes are accurate and reliable, with no modifications or exaggerations. It is important to note that the patient's treatment may have been influenced by local social, economic, health, and epidemiological conditions, which introduces certain limitations. We hope that our colleagues will approach this study with an objective mindset for learning and reference.

Anthrax: A narrative review

Bacillus anthracis is a zoonotic bacterium, majorly responsible for causing human anthrax and the possibility of the outbreak spreading globally. Herbivorous animals serve as the inherent reservoir for the disease, whereas all endothermic species are vulnerable. Humans contract the disease inadvertently by contact with diseased animals or animal products or through the consumption or handling of infected flesh. There is no such reported data indicating the transmission of anthrax from human to human, which further does not guarantee the bacterium's mutations and new transmission route. Nevertheless, it can lead to various infections, including endophthalmitis, bacteremia, cutaneous infection, central nervous system infection, and pneumonia. Therefore, it is crucial to examine the present epidemiological situation of human anthrax in densely populated nations, including the altered symptoms, indications in people, and the method of transmission. This article highlights the current diagnostic methods for human anthrax, further examines the available therapy options and future perspectives in treatment protocol. This narrative review resulted from a simple search strategy on "PubMed", "ScienceDirect", "ClinicalTrials.gov" and web reports using "AND" as Boolean operator with search keywords, i.e., "Anthrax" AND "Infection", "Anthrax" AND "Pandemic", "Anthrax" AND "Infectious disease", "Anthrax" AND "Vaccine", "Anthrax" AND "Diagnosis" shows minimal narrative literature in between 2024 and 2005. Furthermore, this narrative review highlights the potential approaches for detecting anthrax infection, establishing suitable protocols for prevention, and focusing on the current epidemiology and available therapeutics, vaccine and its future developmental strategies for the prevention of infectious disorder.

Probable Case of Cutaneous Anthrax with Toxic Manifestations and Fatality seen in an adolescent in Sokoto, Nigeria: A postmortem review

Background

Anthrax is a life-threatening zoonotic disease caused by Gram-positive, spore-forming bacterium Bacillus anthracis. It manifests as a cutaneous, gastrointestinal, and respiratory disease. The cutaneous form ranges from a self-limiting lesion to severe edematous lesions with toxemic shock. Of recent, increasing cases of anthrax have been reported in Nigeria warranting heightened surveillance. A patient with skin lesions suggestive of cutaneous anthrax and toxic manifestations is reviewed to emphasize the need for a high index of suspicion.

Case report

A 14-year-old boy presented with skin lesions of one month involving the hands, face, and legs, left lower limb swelling of two weeks, fever of 10 days, and fast breathing of five days duration. There was a positive history of contact with cattle carcasses at the abattoir. He was febrile (38.1oc), mildly pale, and mildly dehydrated, oxygen saturation was 95%. He was tachypnoeic and tachycardic with a low-volume pulse. There was extensive left lower limb swelling, a raised necrotic ulcer with a black surface on the calf, measuring 9cmx5cm with serosanguinous discharge, and another confluent vesicular lesion on the anterolateral aspect of the left leg measuring 8cmx6cm. Differential diagnoses considered were cellulitis, osteomyelitis, leishmaniasis, and malignancy.

Result treatment & outcome

His packed cell volume was 33%, retroviral screening, and hepatitis screening were nonreactive, and erythrocyte sedimentation rate was 3mm/hr. Leg X-ray was normal. Other investigations could not be done due to financial constraints and the patient's demise. He received intravenous (IV) fluid, IV ceftriaxone, IV metronidazole, tetanus toxoid, and antiseptic wound dressing. He succumbed to the illness 72 hours later. Anthrax was considered after the patient's demise due to the type of skin lesion and progression of the illness in line with the standard case definition.

Conclusion

Cutaneous anthrax with systemic manifestations should be considered as a probable diagnosis in patients with typical skin lesions and toxic features.

Rational corticosteroids administration and antibiotic treatment is key to managing cutaneous anthrax

BACKGROUND

Anthrax is a global health concern, with cutaneous anthrax accounting for over 95% of cases and generally promising outcomes. Nonetheless, the absence of timely intervention can result in mortality rates of 10-40%. This research aims to explore the clinical presentations and phenotypic characteristics of cutaneous anthrax patients and evaluate the efficacy of various therapeutic approaches.

METHODS

A retrospective study was performed on 76 cutaneous anthrax patients identified at three hospitals from 2017 to 2022. Patients were categorized based on their hospital stay into two groups: those hospitalized for at least seven days and those for shorter durations. We assessed their clinical and phenotypic profiles, including symptoms, general health status, and laboratory findings, alongside treatment outcomes, focusing on corticosteroids therapy and antibiotic regimens.

RESULTS

The study encompassed 76 diagnosed individuals, predominantly young adult males (78.9%). A significant gender disparity was noted. Hormonal treatment markedly improved edema regression in patients (P < 0.002), highlighting its therapeutic value. The impact of various antibiotic treatments on disease progression differed significantly based on corticosteroids treatment status, with specific combinations showing more effectiveness in non-corticosteroids-treated patients.

CONCLUSIONS

The predominance of young male adults among cutaneous anthrax cases was observed, with corticosteroids treatment significantly reducing edema duration. In cases where corticosteroids therapy is not utilized, employing piperacillin-tazobactam alone or in combination with quinolones effectively shortens the illness duration, suggesting a tailored approach to treatment can enhance patient outcomes.

Anthrax in Humans, Animals, and the Environment and the One Health Strategies for Anthrax Control

Anthrax is a notorious disease of public health importance caused by Bacillus anthracis. The causative agent can also be used as a biological weapon. Spores of these bacteria can sustain extreme environmental conditions and remain viable in soil for decades. Domestic and wild ruminants are highly susceptible to this pathogen, which usually presents as a peracute to acute disease. In humans, cutaneous anthrax is frequent but pulmonary and enteric anthrax are more serious. Humans, animals, and the environment are all involved, making anthrax a perfect target for a One Health approach. The environment plays a key role in disease transmission. At a time when the One Health concept is not mere slogans, collaborative efforts of medical professionals, veterinarians, and environmental scientists will be valuable for the prevention and control of this disease. In this review, we discussed the transmission dynamics of anthrax in the environment, animals, and humans, as well as One Health strategies to control and prevent anthrax.

Upper Limb Compartment Syndrome-An Extremely Rare Life-Threatening Complication of Cutaneous Anthrax

(1) Background: Cutaneous anthrax is a disease caused by a Gram-positive bacillus, spore-forming Bacillus anthracis (BA). Cutaneous anthrax accounts for 95% of all anthrax cases, with mortality between 10-40% in untreated forms. The most feared complication, which can be life-threatening and is rarely encountered and described in the literature, is compartment syndrome. (2) Methods: We report a series of six cases of cutaneous anthrax from the same endemic area. In two of the cases, the disease was complicated by compartment syndrome. The systematic review was conducted according to systematic review guidelines, and the PubMed, Google Scholar, and Web of Science databases were searched for publications from 1 January 2008 to 31 December 2023. The keywords used were: "cutaneous anthrax" and "compartment syndrome by cutaneous anthrax". (3) Results: For compartment syndrome, emergency surgical intervention for decompression was required, along with another three surgeries, with hospitalization between 21 and 23 days. In the systematic review, among the 37 articles, 29 did not contain cases focusing on compartment syndrome of the thoracic limb in cutaneous anthrax. The results were included in a Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) flow diagram. (4) Conclusions: Early recognition of the characteristic cutaneous lesions and compartment syndrome with early initiation of antibiotics and urgent surgical treatment is the lifesaving solution.

Identification and characterization of two Bacillus anthracis bacteriophages

Anthrax is an acute infectious zoonotic disease caused by Bacillus anthracis, a bacterium that is considered a potential biological warfare agent. Bacillus bacteriophages shape the composition and evolution of bacterial communities in nature and therefore have important roles in the ecosystem community. B. anthracis phages are not only used in etiological diagnostics but also have promising prospects in clinical therapeutics or for disinfection in anthrax outbreaks. In this study, two temperate B. anthracis phages, vB_BanS_A16R1 (A16R1) and vB_BanS_A16R4 (A16R4), were isolated and showed siphovirus-like morphological characteristics. Genome sequencing showed that the genomes of phages A16R1 and A16R4 are 36,569 bp and 40,059 bp in length, respectively. A16R1 belongs to the genus Wbetavirus, while A16R4 belongs to the genus Hubeivirus and is the first phage of that genus found to lyse B. anthracis. Because these two phages can comparatively specifically lyse B. anthracis, they could be used as alternative diagnostic tools for identification of B. anthracis infections.

Single domain antibodies from camelids in the treatment of microbial infections

Infectious diseases continue to pose significant global health challenges. In addition to the enduring burdens of ailments like malaria and HIV, the emergence of nosocomial outbreaks driven by antibiotic-resistant pathogens underscores the ongoing threats. Furthermore, recent infectious disease crises, exemplified by the Ebola and SARS-CoV-2 outbreaks, have intensified the pursuit of more effective and efficient diagnostic and therapeutic solutions. Among the promising options, antibodies have garnered significant attention due to their favorable structural characteristics and versatile applications. Notably, nanobodies (Nbs), the smallest functional single-domain antibodies of heavy-chain only antibodies produced by camelids, exhibit remarkable capabilities in stable antigen binding. They offer unique advantages such as ease of expression and modification and enhanced stability, as well as improved hydrophilicity compared to conventional antibody fragments (antigen-binding fragments (Fab) or single-chain variable fragments (scFv)) that can aggregate due to their low solubility. Nanobodies directly target antigen epitopes or can be engineered into multivalent Nbs and Nb-fusion proteins, expanding their therapeutic potential. This review is dedicated to charting the progress in Nb research, particularly those derived from camelids, and highlighting their diverse applications in treating infectious diseases, spanning both human and animal contexts.

Case report: Cutaneous anthrax diagnosed using mNGS of a formalin-fixed paraffin-embedded tissue sample

The metagenomic next-generation sequencing (mNGS) method is preferred for genotyping useful for the identification of organisms, illumination of metabolic pathways, and determination of microbiota. It can accurately obtain all the nucleic acid information in the test sample. Anthrax is one of the most important zoonotic diseases, infecting mainly herbivores and occasionally humans. The disease has four typical clinical forms, cutaneous, gastrointestinal, inhalation, and injection, all of which may result in sepsis or meningitis, with cutaneous being the most common form. Here, we report a case of cutaneous anthrax diagnosed by mNGS in a butcher. Histopathology of a skin biopsy revealed PAS-positive bacilli. Formalin-fixed paraffin-embedded (FFPE) tissue sample was confirmed the diagnosis of anthrax by mNGS. He was cured with intravenous penicillin. To our knowledge, this is the first case of cutaneous anthrax diagnosed by mNGS using FFPE tissue. mNGS is useful for identifying pathogens that are difficult to diagnose with conventional methods, and FFPE samples are simple to manage. Compared with traditional bacterial culture, which is difficult to cultivate and takes a long time, mNGS can quickly and accurately help us diagnose anthrax, so that anthrax can be controlled in a timely manner and prevent the outbreak of epidemic events.

Suspected cutaneous anthrax in a yak herder in a highland community in Bhutan, 2023: A case report

This case presents cutaneous anthrax in yak herder from a central highland community in Bhutan. We highlight the clinical presentation, diagnosis and management of the case in a resource-limited setting, and the public health response through the One Health approach.

Anthrax outbreak: exploring its biological agents and public health implications

The (re)emergence of several infectious zoonoses underlines the need for the re-evaluation of the transmission patterns and key players responsible for effective inter-species transfer of diseases. Anthrax is caused by Bacillus anthracis, a zoonotic rod-shaped, Gram-positive, spore-forming bacterium that is highly fatal to both human and animal populations. B. anthracis is widespread across several regions of the world, including Africa, Asia, southern Europe, North and South America, and Australia, and it has a remarkably high attendant impact on the sustainability and profitability of livestock. The current trend in the global distribution of anthrax necessitates an urgent contextual understanding of the key drivers of the spread of B. anthracis in different parts of the world toward the end goal of an anthrax-free world. The understanding of the drivers is integral for the development of control and preventive measures, and also the development of agents such as therapeutics and vaccines against B. anthracis. This review presents a holistic description of the transmission pattern and epidemiology of B. anthracis, and updates on the diagnostic techniques and approaches available for the detection of B. anthracis. In addition, this review highlights plausible prevention and control strategies for the bacterium. This review further underscores the need for participatory epidemiology, hygiene, and safety protocols, the establishment of comprehensive surveillance systems, and global collaborative efforts toward vaccine development as critical steps in controlling anthrax.

Human Exposure to Naturally Occurring Bacillus anthracis in the Kars Region of Eastern Türkiye

Environmental contamination with Bacillus anthracis spores poses uncertain threats to human health. We undertook a study to determine whether inhabitants of the anthrax-endemic region of Kars in eastern Türkiye could develop immune responses to anthrax toxins without recognised clinical infection. We measured anti-PA and anti-LF IgG antibody concentrations by ELISA in serum from 279 volunteers, 105 of whom had previously diagnosed anthrax infection (100 cutaneous, 5 gastrointestinal). Of the 174 without history of infection, 72 had prior contact with anthrax-contaminated material. Individuals were classified according to demographic parameters, daily working environment, and residence type. All villages in this study had recorded previous animal or human anthrax cases. Stepwise regression analyses showed that prior clinical infection correlated strongly with concentrations at the upper end of the ranges observed for both antibodies. For anti-PA, being a butcher and duration of continuous exposure risk correlated with high concentrations, while being a veterinarian or shepherd, time since infection, and town residence correlated with low concentrations. For anti-LF, village residence correlated with high concentrations, while infection limited to fingers or thumbs correlated with low concentrations. Linear discriminant analysis identified antibody concentration profiles associated with known prior infection. Profiles least typical of prior infection were observed in urban dwellers with known previous infection and in veterinarians without history of infection. Four individuals without history of infection (two butchers, two rural dwellers) had profiles suggesting unrecognised prior infection. Healthy humans therefore appear able to tolerate low-level exposure to environmental B. anthracis spores without ill effect, but it remains to be determined whether this exposure is protective. These findings have implications for authorities tasked with reducing the risk posed to human health by spore-contaminated materials and environments.

Unveiling the global reach of African anthrax research: A bibliometric study

Anthrax is a zoonotic bacterial disease caused by Bacillus anthracis. It poses significant threat to humans through contact with infected animals or their by-products. Concerns arise from its long-lasting spore viability and lethality, fuelling its biowarfare potential. Recent anthrax outbreaks across multiple African nations prompted this bibliometric study. The aim of the study was to assess the contributions of African countries, institutions, authors, research funding, and collaborations, while identifying research trends and gaps. We conducted an extensive bibliometric analysis of anthrax-related research publications in Africa from 1923 to 2023, utilizing the Scopus database and VOSviewer. The study covered 364 publications from 32 African countries, accumulating 5,636 citations at an average of 15.5 citations per article, with research articles comprising 88.5% of the corpus. The publication growth rate from 1923 to 2023 was modest at 8.3%, indicating gradual advancement. Notably, there was a significant surge in publications between 2011 and 2023, accounting for 73.1% of total publications. The African research contributions, were categorized into five thematic focuses: ecological dynamics and host interactions, human-livestock anthrax interface, molecular insights into bacterial activity and treatment strategies, collaborative approaches for zoonotic disease prevention, and antibody response and vaccination strategies. Leading institutional contributors included the University of Pretoria and the University of KwaZulu-Natal. Collaborations extended globally to 35 non-African countries, with significant involvement from the United States, United Kingdom, and Germany. Strong African partnerships, especially between Kenya, Nigeria, and South Africa, emerged. The top 10 cited papers explored diverse aspects, including disease impact on wildlife and innovative control strategies, underscoring the importance of multidisciplinary approaches. South Africa played a prominent role, contributing 95 publications and securing funding from various sources, including the National Research Foundation. Collaborations with global institutions highlighted its commitment. This study unveils the dynamic landscape of anthrax research in Africa, emphasizing the pivotal role of collaboration, multidisciplinary One Health approaches, and global partnerships in enhancing research outcomes. Ongoing research and practical solutions for human and animal health remain imperative.

Development of a New Cell-Based AP-1 Gene Reporter Potency Assay for Anti-Anthrax Toxin Therapeutics

Anthrax toxin is a critical virulence factor of Bacillus anthracis. The toxin comprises protective antigen (PA) and two enzymatic moieties, edema factor (EF) and lethal factor (LF), forming bipartite lethal toxin (LT) and edema toxin (ET). PA binds cellular surface receptors and is required for intracellular translocation of the enzymatic moieties. For this reason, anti-PA antibodies have been developed as therapeutics for prophylaxis and treatment of human anthrax infection. Assays described publicly for the control of anti-PA antibody potency quantify inhibition of LT-mediated cell death or the ET-induced increase in c-AMP levels. These assays do not fully reflect and/or capture the pathological functions of anthrax toxin in humans. Herein, we report the development of a cell-based gene reporter potency assay for anti-PA antibodies based on the rapid LT-induced degradation of c-Jun protein, a pathogenic effect that occurs in human cells. This new assay was developed by transducing Hepa1c1c7 cells with an AP-1 reporter lentiviral construct and has been qualified for specificity, accuracy, repeatability, intermediate precision, and linearity. This assay not only serves as a bioassay for LT activity, but has applications for characterization and quality control of anti-PA therapeutic antibodies or other products that target the AP-1 signaling pathway.