Botulism: cause, effects, diagnosis, clinical and laboratory identification, and treatment modalities

Antimicrobial susceptibility of Clostridium botulinum group III field strains isolated in Europe from animal outbreaks

Neurotoxins produced by Clostridium (C.) botulinum group III are responsible for the majority of botulism outbreaks occurring in animals and in this study we report the drug susceptibility of 71 field strains. The minimum inhibitory concentration (MIC) of 13 antimicrobials was established through the agar dilution method. The MIC50 matched or differed for one or two dilutions from MIC90 of the same antimicrobial, showing a unimodal distribution of the MIC values, irrespective of the geographical origin, the animal source and the toxinotype of the strain. Beta-lactams and rifampin showed the lowest MIC values, while gentamicin, polymyxin B and sulfamethoxazole showed the highest MICs. As for similar studies conducted in human botulism, the results could be helpful to avoid the administration of antimicrobials that could worsen the health condition of the affected animals and to develop selective media for the isolation of these fastidious anaerobes. Indeed, the isolation of the strain from affected animals and from environmental samples is important to perform epidemiological studies based on the genetic characterization and to produce tailor-made vaccines.

High risk and low prevalence diseases: Botulism

INTRODUCTION

Botulism is a serious condition that carries with it a high rate of morbidity and mortality.

OBJECTIVE

This review highlights the pearls and pitfalls of botulism, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Botulism is a neuromuscular disorder caused by toxin production of clostridium species bacteria and is a challenging diagnosis that mimics several other conditions. Children account for the majority of patients, with a foodborne source most common, followed by wound sources, typically from intravenous drug injection. Classically, patients with botulism develop bilateral cranial nerve palsies and symmetric, bilateral, descending paralysis. However, patients may initially present with vague symptomatology, such as weakness and dry mouth, which can make diagnosis challenging. A careful history elucidating exposures such as intravenous drug use or consumption of non-commercial canned products can help differentiate botulism from other disorders causing neuromuscular weakness. If suspected, the Centers for Disease Control should be notified to mobilize antitoxin for treatment as soon as the diagnosis is suspected even prior to confirmatory testing. Antibiotics should be avoided in these patients, as they can potentiate toxin release, unless there is a concomitant infection requiring antibiotic therapy. Patients with botulism can develop respiratory compromise requiring emergent airway management. Prolonged neuromuscular blockade from botulism will lead to a variety of symptoms that require comprehensive intensive care unit level care.

CONCLUSION

An understanding of botulism and its many potential mimics can assist emergency clinicians in diagnosing and managing this deadly disease.

Selection of Candidate Monoclonal Antibodies for Therapy of Botulinum Toxin Type A Intoxications

Botulism is one of the most serious food intoxications, manifesting as prolonged paralytic conditions. This disease is usually the result of the consumption of poor quality canned or smoked foods, so the inhabitants of many countries of the world are exposed to the risk of this kind of poisoning every year. In view of the severity of poisonings caused by botulinum neurotoxins, monoclonal antibodies (mAbs) show great promise because of their targeting action, lack of allergic reactions and serum sickness. The use of a cocktail of mAbs increases the "functional specificity" of their mixture, allowing them to bind to the active domains of different toxin chains and block their action. In this work, we obtained 14 murine mAbs to the catalytic and receptor-binding domain of botulinum toxin type A. The Sp2/0-Ag14 murine myeloma cell line and splenocytes from immunized mice of the BALB/c line were used as fusion partners. We have shown that the selected cocktail of three antibodies neutralizes native toxin more effectively than antibodies separately-complete neutralization is achieved at a toxin dose of 3LD50 and partial neutralization at 5LD50. We presume that this cocktail may be promising as a prototype for the creation of a therapeutic drug capable of neutralizing the toxin in the blood of patients.

A Case Report of Acute Bilateral Mydriasis Induced by Herbal Medication

Ma Huang (Ephedra), a traditional herbal remedy, which contains pseudoephedrine and ephedrine, has sympathomimetic characteristics. Despite being banned by the Federal Drug Administration in 2004, it is still used for weight loss and energy boosting in some countries. A previous healthy 42-year-old woman experienced sudden blurred vision in both eyes. Her pupils were dilated to 6 mm each, showing diminished light reflex responses, and were not responsive to both 0.1% and 1% pilocarpine. The day before the onset of her symptoms she had taken a herbal supplement. The woman's herbal medicine was believed to contain ephedrine, a component found in Ma Huang. The sympathomimetic effects of this substance could potentially induce mydriasis. After discontinuing the medication, her symptoms improved over 4 days, leading to a suspicion of drug-induced bilateral mydriasis. Herbal products prescribed for weight loss, which may contain potential elements such as Ma Huang, could lead to unforeseen side effects like bilateral mydriasis, and should be appropriately highlighted.

Botulinum Toxin: A Potential Cardiovascular Agent?

Botulinum neurotoxin (BoNT) is a toxin with a wide repertoire of well-known applications in cosmetics and medicine, such as treating migraine headaches, spasticity, and achalasia, and it has generally been shown to be safe and well-tolerated. In addition to its current successes in clinical practice, studies have also demonstrated the potential of BoNT to be used as a therapeutic agent for many cardiovascular conditions. Prior investigations, as well as trials currently underway, have showcased the safety and potential efficacy of BoNT in applications such as treating ischemia-reperfusion injury, hypertension, atrial fibrillation, and heart failure. While further study in humans, as well as improved statistical power in efficacy studies, are needed before its prospective use as a treatment for the aforementioned conditions, one might consider BoNT a potential cardiovascular agent.

[Clinical and neuroelectrophysiological features of botulism in children: an analysis of eight sporadic cases]

OBJECTIVES

To study the clinical and neuroelectrophysiological features of botulism in children.

METHODS

A retrospective analysis was conducted on the clinical data of eight children who were diagnosed with botulism in the Department of Neurology, Hunan Children's Hospital, from August 2015 to October 2022.

RESULTS

All eight children were found to have symmetrical cranial nerve palsy and flaccid paralysis of the extremities, with a descending pattern. Seven children presented with respiratory muscle paralysis. Electrophysiological examinations revealed decreased compound muscle action potential (CMAP) amplitudes in 5 children, increased CMAP amplitudes exceeding 40.0% in 6 children during high-frequency repetitive nerve stimulation, and short duration, low amplitude, and polyphasic motor unit action potentials in 4 children.

CONCLUSIONS

The main clinical features of botulism in children include symmetric, descending flaccid paralysis starting from cranial nerves, with the possibility of respiratory muscle paralysis. Electrophysiological abnormalities associated with it include decreased CMAP amplitudes, increased CMAP amplitudes during high-frequency repetitive nerve stimulation, and short duration, low amplitude, and polyphasic motor unit action potentials.

Characterization of a novel tetravalent botulism antitoxin based on receptor-binding domain of BoNTs

Botulinum neurotoxin (BoNTs; serotypes A, B, E, and F) cause botulism disease in humans, which could be effectively treated using antitoxins. Herein, we established a novel receptor-binding domain (RBD)-based antitoxin using recombinant C terminal heavy chain (Hc) domains of BoNTs as immunogens. Immunization of horses with these recombinant Hc domains allowed the purification and digestion of IgGs from hyper-immune sera to produce high-quality and high-efficiency monovalent botulism antitoxin F(ab')₂ against each BoNT (M-BATs). However, these M-BATs could not bind or neutralize other serotypes of BoNTs, and that there were no cross-protective effects among these M-BATs. This suggested the need to prepare tetravalent antitoxins to neutralize the four BoNTs simultaneously. Thus, these M-BATs were formulated into a novel tetravalent botulism antitoxin (T-BAT), in which a 10-ml volume contained 10000 IU of BoNT/A and 5000 IU of BoNT/B, BoNT/E, and BoNT/F antitoxins. The novel antitoxin preparation could prevent and treat the four mixed botulinum neurotoxins simultaneously in vivo, representing strong efficacy in an animal poisoning model. Moreover, these antibodies in T-BAT could bind the RBD, whereas conventional antitoxins based on inactivated toxins mainly bind the light chain or heavy chain translocation domain (HN) and weakly bind the important RBD in current experimental conditions. The high levels of RBD-specific novel antitoxins can efficiently bind the RBD and neutralize natural or recombinant toxins containing this RBD. The findings of the present study experimentally support the use of RBD-specific antitoxins to treat BoNT serotype A, B, E, and F-mediated botulism. This study demonstrated the concept of developing potent novel multivalent antitoxins against all BoNTs or other toxins, using the RBD of these toxins as an alternative antigen to inactivated toxins. KEY POINTS: • Antitoxins based on the receptor-binding domains of botulinum neurotoxins were made. • Novel antitoxin binds RBD; traditional antitoxin mainly binds light chain or HN domain. • A tetravalent antitoxin could prevent and treat the four mixed neurotoxins in vivo.

Critical illness-associated weakness and related motor disorders

Weakness of limb and respiratory muscles that occurs in the course of critical illness has become an increasingly common and serious complication of adult and pediatric intensive care unit patients and a cause of prolonged ventilatory support, morbidity, and prolonged hospitalization. Two motor disorders that occur singly or together, namely critical illness polyneuropathy and critical illness myopathy, cause weakness of limb and of breathing muscles, making it difficult to be weaned from ventilatory support, commencing rehabilitation, and extending the length of stay in the intensive care unit, with higher rates of morbidity and mortality. Recovery can take weeks or months and in severe cases, and may be incomplete or absent. Recent findings suggest an improved prognosis of critical illness myopathy compared to polyneuropathy. Prevention and treatment are therefore very important. Its management requires an integrated team approach commencing with neurologic consultation, creatine kinase (CK) measurement, detailed electrodiagnostic, respiratory and neuroimaging studies, and potentially muscle biopsy to elucidate the etiopathogenesis of the weakness in the peripheral and/or central nervous system, for which there may be a variety of causes. These tenets of care are being applied to new cases and survivors of the coronavirus-2 disease pandemic of 2019. This chapter provides an update to the understanding and approach to critical illness motor disorders.

A Thermostable Dissolving Microneedle Vaccine with Recombinant Protein of Botulinum Neurotoxin Serotype A

BACKGROUND

As a Class A bioterrorism agent, botulinum neurotoxin serotype A (BoNT/A) carries the risk of being used by terrorists to cause mass poisoning. The microneedle (MN) patch has a great potential for application as a novel vaccine delivery method. The aim of this study is to develop a thermally stable, dissolving microneedle patch for the delivery of a recombinant protein vaccine using a recombinant C-terminal heavy chain of BoNT/A (Hc of BoNT/A, AHc) to prevent botulism.

METHODS

Fish gelatin, a natural non-toxic and bacteriostatic material, was selected as the microneedle matrix for the preparation of the dissolving microneedle vaccine. Subsequently, the mechanical performance, bacteriostatic properties, vaccination effect, and stability of the microneedle patches were evaluated using instruments such as the displacement-force test station and optical coherence tomography (OCT) scanner.

RESULTS

Fish gelatin matrix at high concentrations has good bacteriostatic properties, and excellent mechanical performance and vaccination effect, meeting the necessities of a vaccine. In both in vivo and in vitro neutralization experiments, MN vaccines containing different antigen doses achieved the same protective efficacy as subcutaneous vaccinations, protecting mice against 10⁶ LD₅₀ of BoNT/A injected intraperitoneally. Thermal stability analysis of the MN vaccines revealed that the fish gelatin matrix protected the AHc vaccine from protein denaturation even after 7 days of storage at 37 °C and enabled the vaccine patches to maintain good immunogenicity and protective efficacy even after 6 months of storage at room temperature.

CONCLUSION

In this study, we successfully prepared a bacteriostatic MN patch using a fish gelatin matrix that not only has a good vaccination effect, but also obviates the need for a cold chain for the AHc vaccine, providing the possibility of rapid, painless, and large-scale vaccination.

Lambert-Eaton Myasthenic Syndrome and Botulism

PURPOSE OF REVIEW

This article reviews the pathophysiology, epidemiology, clinical features, diagnosis, and treatment of Lambert-Eaton myasthenic syndrome (LEMS) and botulism, presynaptic disorders of neuromuscular transmission in which rapid diagnosis improves long-term outcomes.

RECENT FINDINGS

Therapy for LEMS has seen significant advances in recent years due to the approval of amifampridine-based compounds. LEMS is likely still underdiagnosed, particularly when no underlying malignancy is identified. Clinicians must have a strong suspicion for LEMS in any patient presenting with proximal weakness and autonomic dysfunction. Botulism is another rare disorder of presynaptic neuromuscular transmission that is most commonly associated with improper storage or preservation of food products. Over the past 2 decades, wound botulism has been increasingly reported among users of black tar heroin. A high degree of clinical suspicion and electrodiagnostic studies can be beneficial in distinguishing botulism from other acute neurologic disorders, and early involvement of state and federal health authorities may assist in confirming the diagnosis and obtaining treatment. When botulism is suspected, electrodiagnostic studies can provide clinical evidence of disordered neuromuscular transmission in advance of serologic confirmation, and providers should not wait for confirmation of the diagnosis to initiate treatment.

SUMMARY

A targeted clinical history and a thorough neurologic examination with support from serologic and electrodiagnostic studies are key to early diagnosis of LEMS and botulism. Early diagnosis of both conditions creates opportunities for therapy and improves outcomes.

Development and evaluation of a tetravalent botulinum vaccine

Botulinum neurotoxins (BoNTs) are the most toxic known proteins. Naturally occurring botulism in humans is caused by botulinum serotypes A, B, E, and F. Vaccination is an effective strategy to prevent botulism. In this study, a tetravalent botulinum vaccine (TBV) that can prevent serotypes A, B, E, and F was developed using the C-terminal receptor-binding domain of BoNT (Hc) as an antigen. To develop a suitable vaccine formulation, in vitro binding experiments of antigens and aluminum adjuvant in different buffers, and in vivo experiments of TBV at different antigen concentrations, were conducted. Our results showed that the optimal vaccine formulation buffer was a pH 6.0 phosphate buffer, and the suitable antigen concentration was 40 or 80 µg/ml of each antigen. A pilot-scale TBV was then prepared and evaluated for immunogenicity and stability. The results showed that TBV could elicit strong protective efficacy against each BoNT in mice, and remain effective after two years of storage at 4ºC, indicating that the preparation was stable and highly effective. Adsorption experiments also showed that the antigens could be well adsorbed by the aluminum adjuvant after 2 years of storage. Our results provide valuable experimental data supporting the development of a tetravalent botulinum vaccine, which is a promising candidate for the prevention of botulinum serotypes A, B, E, and F.

Human and animal botulism surveillance in France from 2008 to 2019

Botulism is a human and animal neurological disease caused by the action of bacterial neurotoxins (botulinum toxins) produced by bacteria from the genus Clostridium. This disease induces flaccid paralysis that can result in respiratory paralysis and heart failure. Due to its serious potential impact on public health, botulism is a closely monitored notifiable disease in France through a case-based passive surveillance system. In humans, this disease is rare, with an average of 10 outbreaks reported each year, mainly due to the consumption of contaminated foods. Type B and to a lesser extend type A are responsible for the majority of cases of foodborne botulism. Each year, an average of 30 outbreaks are recorded on poultry farms, about 20 cases in wild birds and about 10 outbreaks in cattle, involving a large number of animals. Mosaic forms C/D and D/C in birds and cattle, respectively, are the predominant types in animals in France. Types C and D have also been observed to a lesser extent in animals. With the exception of botulinum toxin E, which was exceptionally detected throughout the period in wild birds, the types of botulism found in animal outbreaks are different from those identified in human outbreaks over the last ten years in France and no human botulism outbreaks investigated have been linked to animal botulism. In line with the One Health concept, we present the first integrative approach to the routine surveillance of botulism in humans and animals in France.

Antidotal treatment of botulism in rats by continuous infusion with 3,4-diaminopyridine

Botulinum neurotoxins (BoNTs) are highly potent, select agent toxins that inhibit neurotransmitter release at motor nerve terminals, causing muscle paralysis and death by asphyxiation. Other than post-exposure prophylaxis with antitoxin, the only treatment option for symptomatic botulism is intubation and supportive care until recovery, which can require weeks or longer. In previous studies, we reported the FDA-approved drug 3,4-diaminopyridine (3,4-DAP) reverses early botulism symptoms and prolongs survival in lethally intoxicated mice. However, the symptomatic benefits of 3,4-DAP are limited by its rapid clearance. Here we investigated whether 3,4-DAP could sustain symptomatic benefits throughout the full course of respiratory paralysis in lethally intoxicated rats. First, we confirmed serial injections of 3,4-DAP stabilized toxic signs and prolonged survival in rats challenged with 2.5 LD50 BoNT/A. Rebound of toxic signs and death occurred within hours after the final 3,4-DAP treatment, consistent with the short half-life of 3,4-DAP in rats. Based on these data, we next investigated whether the therapeutic benefits of 3,4-DAP could be sustained throughout the course of botulism by continuous infusion. To ensure administration of 3,4-DAP at clinically relevant doses, three infusion dose rates (0.5, 1.0 and 1.5 mg/kg∙h) were identified that produced steady-state serum levels of 3,4-DAP consistent with clinical dosing. We then compared dose-dependent effects of 3,4-DAP on toxic signs and survival in rats intoxicated with 2.5 LD50 BoNT/A. In contrast to saline vehicle, which resulted in 100% mortality, infusion of 3,4-DAP at ≥ 1.0 mg/kg∙h from 1 to 14 d after intoxication produced 94.4% survival and full resolution of toxic signs, without rebound of toxic signs after infusion was stopped. In contrast, withdrawal of 3,4-DAP infusion at 5 d resulted in re-emergence of toxic sign and death within 12 h, confirming antidotal outcomes require sustained 3,4-DAP treatment for longer than 5 d after intoxication. We exploited this novel survival model of lethal botulism to explore neurophysiological parameters of diaphragm paralysis and recovery. While neurotransmission was nearly eliminated at 5 d, neurotransmission was significantly improved at 21 d in 3,4-DAP-infused survivors, although still depressed compared to naïve rats. 3,4-DAP is the first small molecule to reverse systemic paralysis and promote survival in animal models of botulism, thereby meeting a critical treatment need that is not addressed by post-exposure prophylaxis with conventional antitoxin. These data contribute to a growing body of evidence supporting the use of 3,4-DAP to treat clinical botulism.

Highly Specific Monoclonal Antibody Targeting the Botulinum Neurotoxin Type E Exposed SNAP-25 Neoepitope

Botulinum neurotoxin type E (BoNT/E), the fastest acting toxin of all BoNTs, cleaves the 25 kDa synaptosomal-associated protein (SNAP-25) in motor neurons, leading to flaccid paralysis. The specific detection and quantification of the BoNT/E-cleaved SNAP-25 neoepitope can facilitate the development of cell-based assays for the characterization of anti-BoNT/E antibody preparations. In order to isolate highly specific monoclonal antibodies suitable for the in vitro immuno-detection of the exposed neoepitope, mice and rabbits were immunized with an eight amino acid peptide composed of the C-terminus of the cleaved SNAP-25. The immunized rabbits developed a specific and robust polyclonal antibody response, whereas the immunized mice mostly demonstrated a weak antibody response that could not discriminate between the two forms of SNAP-25. An immune scFv phage-display library was constructed from the immunized rabbits and a panel of antibodies was isolated. The sequence alignment of the isolated clones revealed high similarity between both heavy and light chains with exceptionally short HCDR3 sequences. A chimeric scFv-Fc antibody was further expressed and characterized, exhibiting a selective, ultra-high affinity (pM) towards the SNAP-25 neoepitope. Moreover, this antibody enabled the sensitive detection of cleaved SNAP-25 in BoNT/E treated SiMa cells with no cross reactivity with the intact SNAP-25. Thus, by applying an immunization and selection procedure, we have isolated a novel, specific and high-affinity antibody against the BoNT/E-derived SNAP-25 neoepitope. This novel antibody can be applied in in vitro assays that determine the potency of antitoxin preparations and reduce the use of laboratory animals for these purposes.

Harnessing the Natural Toxic Metabolites in COVID-19

SARS-CoV-2 is a novel coronavirus and the cause of the recent pandemic; it is an enveloped β-coronavirus. SARS-CoV-2 appear in the Wuhan City of China for the first time and outspread worldwide quickly. Due to its person-to-person fast transmission, COVID-19 is becoming a global problem. SARS-CoV-2 enter into cells by using ACE2 receptors that are numerous in the lungs and finally can cause acute respiratory distress syndrome (ARDS). Dry cough, sore throat, fever, body pain, headache, GIT discomfort, diarrhoea, and fatigue are some of the COVID-19 symptoms. There is no definite and certain treatment for disease caused by SARS-CoV-2 till now. Some pharmacological effects of toxins, toxoids, and venoms have been proven, and their effects on some diseases have been evaluated. This study aimed to investigate the role of toxins, toxoids, and venom in the pathophysiology of COVID-19 disease.

Immunogenicity of Botulinum Toxin Formulations: Potential Therapeutic Implications

Botulinum neurotoxins (BoNTs) are proteins produced by bacteria of the Clostridium family. Upon oral ingestion, BoNT causes the neuroparalytic syndrome botulism. There are seven serotypes of BoNT (serotypes A-G); BoNT-A and BoNT-B are the botulinum toxin serotypes utilized for therapeutic applications. Treatment with BoNT injections is used to manage chronic medical conditions across multiple indications. As with other biologic drugs, immunogenicity after long-term treatment with BoNT formulations may occur, and repeated use can elicit antibody formation leading to clinical nonresponsiveness. Thus, approaching BoNT treatment of chronic conditions with therapeutic formulations that minimize stimulating the host immune response while balancing patient responsiveness to therapy is ideal. Immunogenicity is a clinical limitation in many settings that use biologic drugs for treatment, and clinically relevant immunogenicity reduction has been achieved through engineering smaller protein constructs and reducing unnecessary formulation components. A similar approach has influenced the evolution of BoNT formulations. Three BoNT-A products and one BoNT-B product have been approved by the Food and Drug Administration (FDA) for therapeutic use: onabotulinumtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, and rimabotulinumtoxinB; a fourth BoNT-A product, daxibotulinumtoxinA, is currently under regulatory review. Additionally, prabotulinumtoxinA is a BoNT-A product that has been approved for aesthetic indications but not therapeutic use. Here, we discuss the preclinical and clinical immunogenicity data that exist within the scientific literature and provide a perspective for considering immunogenicity as a key factor in choice of BoNT formulation.

Current Developments in Diagnostic Assays for Laboratory Confirmation and Investigation of Botulism

Detection of botulinum neurotoxin or isolation of the toxin producing organism is required for the laboratory confirmation of botulism in clinical specimens. In an effort to reduce animal testing required by the gold standard method of botulinum neurotoxin detection, the mouse bioassay, many technologies have been developed to detect and characterize the causative agent of botulism. Recent advancements in these technologies have led to improvements in technical performance of diagnostic assays; however, many emerging assays have not been validated for the detection of all serotypes in complex clinical and environmental matrices. Improvements to culture protocols, endopeptidase-based assays, and a variety of immunological and molecular methods have provided laboratories with a variety of testing options to evaluate and incorporate into their testing algorithms. While significant advances have been made to improve these assays, additional work is necessary to evaluate these methods in various clinical matrices and to establish standardized criteria for data analysis and interpretation.

A Rabbit Model for the Evaluation of Drugs for Treating the Chronic Phase of Botulism

Antitoxin, the only licensed drug therapy for botulism, neutralizes circulating botulinum neurotoxin (BoNT). However, antitoxin is no longer effective when a critical amount of BoNT has already entered its target nerve cells. The outcome is a chronic phase of botulism that is characterized by prolonged paralysis. In this stage, blocking toxin activity within cells by next-generation intraneuronal anti-botulinum drugs (INABDs) may shorten the chronic phase of the disease and accelerate recovery. However, there is a lack of adequate animal models that simulate the chronic phase of botulism for evaluating the efficacy of INABDs. Herein, we report the development of a rabbit model for the chronic phase of botulism, induced by intoxication with a sublethal dose of BoNT. Spirometry monitoring enabled us to detect deviations from normal respiration and to quantitatively define the time to symptom onset and disease duration. A 0.85 rabbit intramuscular median lethal dose of BoNT/A elicited the most consistent and prolonged disease duration (mean = 11.8 days, relative standard deviation = 27.9%) that still enabled spontaneous recovery. Post-exposure treatment with antitoxin at various time points significantly shortened the disease duration, providing a proof of concept that the new model is adequate for evaluating novel therapeutics for botulism.

Neutralizing Concentrations of Anti-Botulinum Toxin Antibodies Positively Correlate with Mouse Neutralization Assay Results in a Guinea Pig Model

Botulinum neurotoxins (BoNT) are some of the most toxic proteins known and can induce respiratory failure requiring long-term intensive care. Treatment of botulism includes the administration of antitoxins. Monoclonal antibodies (mAbs) hold considerable promise as BoNT therapeutics and prophylactics, due to their potency and safety. A three-mAb combination has been developed that specifically neutralizes BoNT serotype A (BoNT/A), and a separate three mAb combination has been developed that specifically neutralizes BoNT serotype B (BoNT/B). A six mAb cocktail, designated G03-52-01, has been developed that combines the anti-BoNT/A and anti-BoNT/B mAbs. The pharmacokinetics and neutralizing antibody concentration (NAC) of G03-52-01 has been determined in guinea pigs, and these parameters were correlated with protection against an inhalation challenge of BoNT/A1 or BoNT/B1. Previously, it was shown that each antibody demonstrated a dose-dependent mAb serum concentration and reached maximum circulating concentrations within 48 h after intramuscular (IM) or intraperitoneal (IP) injection and that a single IM injection of G03-52-01 administered 48 h pre-exposure protected guinea pigs against an inhalation challenge of up to 93 LD₅₀s of BoNT/A1 and 116 LD₅₀s of BoNT/B1. The data presented here advance our understanding of the relationship of the neutralizing NAC to the measured circulating antibody concentration and provide additional support that a single IM or intravenous (IV) administration of G03-52-01 will provide pre-exposure prophylaxis against botulism from an aerosol exposure of BoNT/A and BoNT/B.

A Novel Running Wheel Mouse Model for Botulism and Its Use for the Evaluation of Postsymptom Antitoxin Efficacy

Antitoxin is currently the only approved therapy for botulinum intoxications. The efficacy of antitoxin preparations is evaluated in animals. However, while in practice antitoxin is administered to patients only after symptom onset, in most animal studies, it is tested in relation to time postintoxication. This may be attributed to difficulties in quantitating early botulism symptoms in animals. In the current study, a novel system based on high-resolution monitoring of mouse activity on a running wheel was developed to allow evaluation of postsymptom antitoxin efficacy. The system enables automatic and remote monitoring of 48 mice simultaneously. Based on the nocturnal activity patterns of individual naive mice, two criteria were defined as the onset of symptoms. Postsymptom treatment with a human-normalized dose of antitoxin was fully protective in mice exposed to 4 50% lethal doses (LD₅₀s) of botulinum neurotoxin serotype A (BoNT/A) and BoNT/B. Moreover, for the first time, a high protection rate was obtained in mice treated postsymptomatically, following a challenge with BoNT/E, the fastest-acting BoNT. The running wheel system was further modified to develop a mouse model for the evaluation of next-generation therapeutics for progressive botulism at time points where antitoxin is not effective. Exposure of mice to 0.3 LD₅₀ of BoNT/A resulted in long-lasting paralysis and a reduction in running activity for 16 to 18 days. Antitoxin treatment was no longer effective when administered 72 h postintoxication, defining the time window to evaluate next-generation therapeutics. Altogether, the running wheel systems presented herein offer quantitative means to evaluate the efficacy of current and future antibotulinum drugs.

Developing Recombinant Antibodies by Phage Display Against Infectious Diseases and Toxins for Diagnostics and Therapy

Antibodies are essential molecules for diagnosis and treatment of diseases caused by pathogens and their toxins. Antibodies were integrated in our medical repertoire against infectious diseases more than hundred years ago by using animal sera to treat tetanus and diphtheria. In these days, most developed therapeutic antibodies target cancer or autoimmune diseases. The COVID-19 pandemic was a reminder about the importance of antibodies for therapy against infectious diseases. While monoclonal antibodies could be generated by hybridoma technology since the 70ies of the former century, nowadays antibody phage display, among other display technologies, is robustly established to discover new human monoclonal antibodies. Phage display is an in vitro technology which confers the potential for generating antibodies from universal libraries against any conceivable molecule of sufficient size and omits the limitations of the immune systems. If convalescent patients or immunized/infected animals are available, it is possible to construct immune phage display libraries to select in vivo affinity-matured antibodies. A further advantage is the availability of the DNA sequence encoding the phage displayed antibody fragment, which is packaged in the phage particles. Therefore, the selected antibody fragments can be rapidly further engineered in any needed antibody format according to the requirements of the final application. In this review, we present an overview of phage display derived recombinant antibodies against bacterial, viral and eukaryotic pathogens, as well as microbial toxins, intended for diagnostic and therapeutic applications.

Open Tibial Fracture Complicated by Wound Botulism: A Case Study

Botulism is a neuroparalytic disease most commonly caused by foodborne ingestion of neurotoxin types A, B, and E, and is often fatal if untreated. Clinicians should be able to recognize the classic symptoms of botulinum intoxication (12). Owing to its rarity, there are a limited number of studies evaluating the clinical care of patients with wound botulism (10). We present an infected tibial non-union with botulism who underwent a successful radical excision and bone transport. The patient tolerated the procedure well.

Safety, Tolerability, and Pharmacokinetics of NTM-1632, a Novel Mixture of Three Monoclonal Antibodies against Botulinum Toxin B

Botulism is a rare, life-threatening paralytic disease caused by Clostridium botulinum neurotoxin (BoNT). Available treatments, including an equine antitoxin and human immune globulin, are given postexposure and challenging to produce and administer. NTM-1632 is an equimolar mixture of 3 human IgG monoclonal antibodies, B1, B2, and B3, targeting BoNT serotype B (BoNT/B). This first-in-human study assessed the safety, tolerability, pharmacokinetics (PK), and immunogenicity of NTM-1632. This double-blind, single-center, placebo-controlled dose escalation study randomized 3 cohorts of healthy volunteers to receive a single intravenous dose of NTM-1632 (0.033, 0.165, or 0.330 mg/kg) or saline placebo. Safety monitoring included physical examinations, clinical laboratory studies, and vital signs. Blood sampling was performed at prespecified time points for PK and immunogenicity analyses. Twenty-four subjects received study product (18 NTM-1632; 6 placebo), and no deaths or serious adverse events were reported. Adverse events in the NTM-1632 groups were generally mild and similar in frequency and severity to the placebo group, and no safety signal was identified. NTM-1632 has a favorable PK profile with a half-life of >20 days for the 0.330-mg/kg dose and an approximately linear relationship with respect to maximum concentration and area under the concentration-time curve (AUC_0→t). NTM-1632 demonstrated low immunogenicity with only a few treatment-emergent antidrug antibody responses in the low and middle dosing groups and none at the highest dose. NTM-1632 is well tolerated at the administered doses. The favorable safety, PK, and immunogenicity profile of NTM-1632 supports further clinical development as a treatment for BoNT/B intoxication and postexposure prophylaxis. (This study has been registered at ClinicalTrials.gov under identifier NCT02779140.).

A Monoclonal Antibody Combination against both Serotypes A and B Botulinum Toxin Prevents Inhalational Botulism in a Guinea Pig Model

Botulinum neurotoxins (BoNT) are extremely potent and can induce respiratory failure, requiring long-term intensive care to prevent death. Recombinant monoclonal antibodies (mAbs) hold considerable promise as BoNT therapeutics and prophylactics. In contrast, equine antitoxin cannot be used prophylactically and has a short half-life. Two three-mAb combinations are in development that specifically neutralize BoNT serotype A (BoNT/A) and B (BoNT/B). The three-mAb combinations addressing a single serotype provided pre-exposure prophylaxis in the guinea pig inhalation model. A lyophilized co-formulation of six mAbs, designated G03-52-01, that addresses both A and B serotypes is in development. Here, we investigated the efficacy of G03-52-01 to protect guinea pigs against an aerosol exposure challenge of BoNT/A1 or BoNT/B1. Previously, it was found that each antibody demonstrated a dose-dependent exposure and reached maximum circulating concentrations within 48 h after intramuscular (IM) or intravenous (IV) injection. Here we show that G03-52-01, in a single IM injection of G03-52-01 administered 48 h pre-exposure, protected guinea pigs against an aerosol challenge of up to 238 LD₅₀s of BoNT/A1 and 191 LD₅₀s of BoNT/B1. These data suggest that a single IM administration of G03-52-01 provides pre-exposure prophylaxis against botulism from an aerosol exposure of BoNT/A1 or BoNT/B1.

Clinical Predictive Values in Botulism: A 10-year Survey

Background

Botulism occurs periodically or in outbreaks in Iran. Botulism is lethal and accordingly a considerable issue in environmental health, although it is uncommon. This study was performed to evaluate the potential predictive factors in foodborne botulism in a 10-year span.

Materials and methods

All medical records from patients with foodborne botulism admitted to Imam Reza Hospital in 10 years (2005-2015) were analyzed retrospectively.

Results

61 cases were included (38 men, mean age ± SD 28.93 ± 19.14 years). All cases were treated with antitoxin. 6.6% of cases died. Canned beans were correlated with the admission to intensive care unit (ICU), and also, it increased the length of ICU stay significantly (P = 0.007 and 0.023, respectively). The incidence of dizziness and diplopia significantly induced excess demands for higher doses of antitoxin (P = 0.038 and 0.023, respectively). Risk of dysphagia was remarkably higher in cases with ptosis (P = 0.039, odds ratio: 3). While in this study, time elapsed between the onset of clinical manifestations and antitoxin administration was correlated with the occurrence of dysphagia, constipation, and blurred vision, and early treatment did not improve the outcomes. Multiple analysis of potential variables by a logistic regression model disclosed that the independent significant factors affecting mortality were the need for mechanical ventilation (P = 0.000), dyspnea (P = 0.044), general weakness (P = 0.044), and lack of consciousness (P = 0.008) at the time of admission.

Conclusions

Taking clinical signs and symptoms into account upon patient arrival is important and, of course, is a key to further management in the emergency setting.

How to cite this article

Saeidi S, Dadpour B, Jarahi L, Ghamsari AA, Nooghabi MN. Clinical Predictive Values in Botulism: A 10-year Survey. Indian J Crit Care Med 2021;25(4):411-415.

Early recovery of botulism: one decade of experience

BACKGROUND

Botulism is a rare but serious disease, which appears in different forms. In this study, we reviewed the clinical features, laboratory data, and outcomes of patients who referred to our tertiary center.

MATERIALS AND METHODS

All confirmed cases of botulism referred to an academic referral center and a teaching hospital during 2009-2019, were retrospectively reviewed.

RESULTS

Fifty-three cases of clinical or laboratory-confirmed botulism were examined in this study. Nineteen patients were confirmed by laboratory data (serotype A (89.5%) and serotype E (10.5%)). In seven cases, the cause of botulism was unclear. In two patients, systemic symptoms emerged after the therapeutic injection of botulinum neurotoxin. The majority of cases (83%) were caused by an obvious food source. In 66% of cases, the initial symptoms emerged within less than 36 h, while in 20.8% of cases, the symptoms developed within or after 36 h; however, in seven patients that their botulism sources were unclear, the onset could not be estimated. All patients showed cranial involvement and generalized manifestation, and 49.1% had gastrointestinal symptoms. Except for two patients who were not treated due to immediate drug reactions who manifested severe hemodynamic instability, the rest of the patients were treated with trivalent antitoxin (A, B, and E). The complete resolution of the symptoms during hospitalization was documented in 50.9% of the patients. About 17% of the patients were intubated. Two patients died due to massive bilateral pulmonary thromboembolism and cardiac asystole following respiratory failure.

CONCLUSIONS

Although the complete resolution of the symptoms usually takes several weeks, in our experience, most patients showed at least partial resolution upon discharge. Early treatment results in better outcomes.

Description of Clostridium cagae sp. nov., Clostridium rectalis sp. nov. and Hathewaya massiliensis sp. nov., new anaerobic bacteria isolated from human stool samples

Using culturomics methods, three strains were isolated, identified and characterized following the taxonogenomics concept. Clostridium cagae strain Marseille-P4344T (=CSURP4344), Clostridium rectalis strain Marseille-P4200T (=CSURP4200) and Hathewaya massiliensis strain Marseille-P3545T (=CSURP3545) were isolated from human stool samples. The phylogenetic reconstruction, phenotypic criteria and genomic analyses were carried out and demonstrated that these three bacteria are different from previously known bacterial species with standing in nomenclature and were classified as new members of the Clostridiaceae family.

Docking Simulation and Sandwich Assay for Aptamer-Based Botulinum Neurotoxin Type C Detection

Aptamers are biomaterials that bind to a target molecule through a unique structure, and have high applicability in the diagnostic and medical fields. To effectively utilize aptamers, it is important to analyze the structure of the aptamer binding to the target molecule; however, there are difficulties in experimentally identifying this structure. In the modern pharmaceutical industry, computer-driven docking simulations that predict intermolecular binding models are used to select candidates that effectively bind target molecules. Botulinum toxin (BoNT) is the most poisonous neurotoxin produced from the Clostridium botulinum bacteria, and BoNT/C, one of the eight serotypes, causes paralysis in livestock. In this study, the aptamers that bound to BoNT/C were screened via the systematic evolution of ligands by exponential enrichment, and the binding affinity analysis and binding model were evaluated to select optimal aptamers. Based on surface plasmon resonance analysis and molecular operating environment docking simulation, a pair of aptamers that had high binding affinity to BoNT/C and were bound to different BoNT/C sites were selected. A sandwich assay based on this aptamer pair detected the BoNT/C protein to a concentration as low as ~0.2 ng Ml^-1. These results show that docking simulations are a useful strategy for screening aptamers that bind to specific targets.

Foodborne Botulism: Clinical Diagnosis and Medical Treatment

Botulinum neurotoxins (BoNTs) produced by Clostridia species are the most potent identified natural toxins. Classically, the toxic neurological syndrome is characterized by an (afebrile) acute symmetric descending flaccid paralysis. The most know typical clinical syndrome of botulism refers to the foodborne form. All different forms are characterized by the same symptoms, caused by toxin-induced neuromuscular paralysis. The diagnosis of botulism is essentially clinical, as well as the decision to apply the specific antidotal treatment. The role of the laboratory is mandatory to confirm the clinical suspicion in relation to regulatory agencies, to identify the BoNTs involved and the source of intoxication. The laboratory diagnosis of foodborne botulism is based on the detection of BoNTs in clinical specimens/food samples and the isolation of BoNT from stools. Foodborne botulism intoxication is often underdiagnosed; the initial symptoms can be confused with more common clinical conditions (i.e., stroke, myasthenia gravis, Guillain–Barré syndrome—Miller–Fisher variant, Eaton–Lambert syndrome, tick paralysis and shellfish or tetrodotoxin poisoning). The treatment includes procedures for decontamination, antidote administration and, when required, support of respiratory function; few differences are related to the different way of exposure.

Perspectives for the use of therapeutic Botulinum toxin as a multifaceted candidate drug to attenuate COVID-19

The recent outbreak of coronavirus disease (COVID-19) resulting from a distinctive severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) continues to evolve in many countries and pose life-threatening clinical issues to global public health. While the lungs are the primary target for the SARS-CoV-2-mediated pathological consequence, the virus appears to invade the brain and cause unpredicted neurological deficits. In the later stage, COVID-19 can progress to pneumonia, acute respiratory failure, neurodegeneration and multi-organ dysfunctions leading to death. Though a significant portion of individuals with COVID-19 has been recovering from clinical symptoms, the pathological impact of the SARS-CoV-2 infection on the structural and functional properties of the lungs, heart, brain and other organs at the post-recovery state remains unknown. Presently, there is an urgent need for a remedial measure to combat this devastating COVID-19. Botulinum toxins (BoNTs) are potent neurotoxins that can induce paralysis of muscle and acute respiratory arrest in humans. However, a mild dose of the purified form of BoNT has been known to attenuate chronic cough, dyspnoea, pneumonia, acute respiratory failure, abnormal circulation, cardiac defects and various neurological deficits that have been recognised as the prominent clinical symptoms of COVID-19. Considering the fact, this review article provides 1) an overview of the SARS-CoV-2 mediated pathological impact on the lungs, heart and brain, 2) signifies the therapeutic uses of BoNTs against pulmonary failure, cardiac arrest and neurological deficits, and 3) emphasize the rationality for the possible use of BoNT to prevent SARS-CoV-2 infection and manage COVID-19.

Critical Analysis of Neuronal Cell and the Mouse Bioassay for Detection of Botulinum Neurotoxins

Botulinum Neurotoxins (BoNTs) are a large protein family that includes the most potent neurotoxins known to humankind. BoNTs delivered locally in humans at low doses are widely used pharmaceuticals. Reliable and quantitative detection of BoNTs is of paramount importance for the clinical diagnosis of botulism, basic research, drug development, potency determination, and detection in clinical, environmental, and food samples. Ideally, a definitive assay for BoNT should reflect the activity of each of the four steps in nerve intoxication. The in vivo mouse bioassay (MBA) is the 'gold standard' for the detection of BoNTs. The MBA is sensitive, robust, semi-quantitative, and reliable within its sensitivity limits. Potential drawbacks with the MBA include assay-to-assay potency variations, especially between laboratories, and false positives or negatives. These limitations can be largely avoided by careful planning and performance. Another detection method that has gained importance in recent years for research and potency determination of pharmaceutical BoNTs is cell-based assays, as these assays can be highly sensitive, quantitative, human-specific, and detect fully functional holotoxins at physiologically relevant concentrations. A myriad of other in vitro BoNT detection methods exist. This review focuses on critical factors and assay limitations of the mouse bioassay and cell-based assays for BoNT detection.

Therapeutic efficacy of equine botulism heptavalent antitoxin against all seven botulinum neurotoxins in symptomatic guinea pigs

Botulism neurotoxins are highly toxic and are potential agents for bioterrorism. The development of effective therapy is essential to counter the possible use of these toxins in military and bioterrorism scenarios, and to provide treatment in cases of natural intoxication. Guinea pigs were intoxicated with a lethal dose of botulinum neurotoxin serotypes A, B, C, D, E, F or G, and at onset of the clinical disease intoxicated animals were treated with either BAT^® [Botulism Antitoxin Heptavalent (A, B, C, D, E, F, G)–(Equine)] or placebo. BAT product treatment significantly (p<0.0001) enhanced survival compared to placebo for all botulinum neurotoxin serotypes and arrested or mitigated the progression of clinical signs of botulism intoxication. These results demonstrated the therapeutic efficacy of BAT product in guinea pigs and provided supporting evidence of effectiveness for licensure of BAT product under FDA 21 CFR Part 601 (Subpart H Animal Rule) as a therapeutic for botulism intoxication to serotypes A, B, C, D, E, F or G in adults and pediatric patients.

Hospital-acquired intestinal toxemia botulism in a newly diagnosed adult colon cancer patient

This manuscript reports a case of intestinal toxemia botulism in an adult with recently diagnosed metastatic colon cancer in whom botulism symptoms began 23 days after hospital admission. Representing the rarest form of botulism presentation in clinical practice, this infectious disease may have developed due to a cluster of predisposing factors that favored Clostridium botulinum colonization and the endogenous production of neurotoxins, among which are previous use of broad-spectrum antibiotics and colon changes related to the development of the neoplasia. This case highlights the importance of considering intestinal toxemia botulism in the differential diagnosis of a patient presenting with symmetrical descending flaccid paralysis, since immediate treatment with botulinum antitoxin may improve clinical outcomes.

Rapid Detection of Botulinum Neurotoxins-A Review

A toxin is a poisonous substance produced within living cells or organisms. One of the most potent groups of toxins currently known are the Botulinum Neurotoxins (BoNTs). These are so deadly that as little as 62 ng could kill an average human; to put this into context that is approximately 200,000 × less than the weight of a grain of sand. The extreme toxicity of BoNTs leads to the need for methods of determining their concentration at very low levels of sensitivity. Currently the mouse bioassay is the most widely used detection method monitoring the activity of the toxin; however, this assay is not only lengthy, it also has both cost and ethical issues due to the use of live animals. This review focuses on detection methods both existing and emerging that remove the need for the use of animals and will look at three areas; speed of detection, sensitivity of detection and finally cost. The assays will have wide reaching interest, ranging from the pharmaceutical/clinical industry for production quality management or as a point of care sensor in suspected cases of botulism, the food industry as a quality control measure, to the military, detecting BoNT that has been potentially used as a bio warfare agent.

Development and evaluation of candidate subunit vaccine and novel antitoxin against botulinum neurotoxin serotype E

Botulinum neurotoxins (BoNTs) are among the most toxic proteins. Vaccination is an effective strategy to prevent botulism. To generate a vaccine suitable for human use, a recombinant non-His-tagged isoform of the Hc domain of botulinum neurotoxin serotype E (rEHc) was expressed in Escherichia coli and purified by sequential chromatography. The immunogenicity of rEHc was evaluated in mice and dose- and time-dependent immune responses were observed in both antibody titers and protective potency. Then, the pilot-scale expression and purification of rEHc were performed, and its immunological activity was characterized. Our results showed rEHc has good immunogenicity and can elicit strong protective potency against botulinum neurotoxin serotype E (BoNT/E) in mice, indicating that rEHc is an effective botulism vaccine candidate. Further, we developed a novel antitoxin against BoNT/E by purifying F(ab')₂ from pepsin-digested serum IgG of rEHc-inoculated horses. The protective effect of the F(ab')₂ antitoxin was determined in vitro and in vivo. The results showed that our F(ab')₂ antitoxin can prevent botulism in BoNT/E-challenged mice and effectively alleviate the progression of paralysis caused by BoNT/E to achieve therapeutic effects. Therefore, our results provide valuable experimental data for the production of a novel antitoxin, which is a promising candidate for the treatment of BoNT/E-induced botulism.

Medical treatment for botulism

BACKGROUND

Botulism is an acute paralytic illness caused by a neurotoxin produced by Clostridium botulinum. Supportive care, including intensive care, is key, but the role of other medical treatments is unclear. This is an update of a review first published in 2011.

OBJECTIVES

To assess the effects of medical treatments on mortality, duration of hospitalization, mechanical ventilation, tube or parenteral feeding, and risk of adverse events in botulism.

SEARCH METHODS

We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, and Embase on 23 January 2018. We reviewed bibliographies and contacted authors and experts. We searched two clinical trials registers, WHO ICTRP and clinicaltrials.gov, on 21 February 2019.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and quasi-RCTs examining the medical treatment of any of the four major types of botulism (infant intestinal botulism, food-borne botulism, wound botulism, and adult intestinal toxemia). Potential medical treatments included equine serum trivalent botulism antitoxin, human-derived botulinum immune globulin intravenous (BIG-IV), plasma exchange, 3,4-diaminopyridine, and guanidine.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methodology.Our primary outcome was in-hospital death from any cause occurring within four weeks from randomization or the beginning of treatment. Secondary outcomes were death from any cause occurring within 12 weeks, duration of hospitalization, duration of mechanical ventilation, duration of tube or parenteral feeding, and proportion of participants with adverse events or complications of treatment.

MAIN RESULTS

A single RCT met the inclusion criteria. Our 2018 search update identified no additional trials. The included trial evaluated BIG-IV for the treatment of infant botulism and included 59 treatment participants and 63 control participants. The control group received a control immune globulin that did not have an effect on botulinum toxin. Participants were followed during the length of their hospitalization to measure the outcomes of interest. There was some violation of intention-to-treat principles, and possibly some between-treatment group imbalances among participants admitted to the intensive care unit and mechanically ventilated, but otherwise the risk of bias was low. There were no deaths in either group, making any treatment effect on mortality inestimable. There was a benefit in the treatment group on mean duration of hospitalization (BIG-IV: 2.60 weeks, 95% confidence interval (CI) 1.95 to 3.25; control: 5.70 weeks, 95% CI 4.40 to 7.00; mean difference (MD) -3.10 weeks, 95% CI -4.52 to -1.68; moderate-certainty evidence); mechanical ventilation (BIG-IV: 1.80 weeks, 95% CI 1.20 to 2.40; control: 4.40 weeks, 95% CI 3.00 to 5.80; MD -2.60 weeks, 95% CI -4.06 to -1.14; low-certainty evidence); and tube or parenteral feeding (BIG-IV: 3.60 weeks, 95% CI 1.70 to 5.50; control: 10.00 weeks, 95% CI 6.85 to 13.15; MD -6.40 weeks, 95% CI -10.00 to -2.80; moderate-certainty evidence), but not on proportion of participants with adverse events or complications (BIG-IV: 63.08%; control: 68.75%; risk ratio 0.92, 95% CI 0.72 to 1.18; absolute risk reduction 0.06, 95% CI 0.22 to -0.11; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

We found low- and moderate-certainty evidence supporting the use of BIG-IV in infant intestinal botulism. A single RCT demonstrated that BIG-IV probably decreases the duration of hospitalization; may decrease the duration of mechanical ventilation; and probably decreases the duration of tube or parenteral feeding. Adverse events were probably no more frequent with immune globulin than with placebo. Our search did not reveal any evidence examining the use of other medical treatments including serum trivalent botulism antitoxin.

Monoclonal Antibody Combinations Prevent Serotype A and Serotype B Inhalational Botulism in a Guinea Pig Model

Botulinum neurotoxins (BoNT) are some of the most toxic proteins known, with a human LD₅₀ of ~1 ng/kg. Equine antitoxin has a half-life in circulation of less than 1 day and is limited to a treatment rather than a prevention indication. The development of monoclonal antibodies (mAbs) may represent an alternative therapeutic option that can be produced at high quantities and of high quality and with half-lives of >10 days. Two different three mAb combinations are being developed that specifically neutralize BoNT serotypes A (BoNT/A) and B (BoNT/B). We investigated the pharmacokinetics of the anti-BoNT/A and anti-BoNT/B antibodies in guinea pigs (Cavia porcellus) and their ability to protect guinea pigs against an aerosol challenge of BoNT/A1 or BoNT/B1. Each antibody exhibited dose-dependent exposure and reached maximum circulating concentrations within 48 h post intraperitoneal or intramuscular injection. A single intramuscular dose of the three mAb combination protected guinea pigs against an aerosol challenge dose of 93 LD₅₀ of BoNT/A1 and 116 LD₅₀ of BoNT/B1 at 48 h post antibody administration. These mAbs are effective in preventing botulism after an aerosol challenge of BoNT/A1 and BoNT/B1 and may represent an alternative to vaccination to prevent type A or B botulism in those at risk of BoNT exposure.

Foodborne botulism in Turkey, 1983 to 2017

OBJECTIVE

The aim of this study is to assess the epidemiology of foodborne botulism cases which were seen and published in Turkey.

MATERIAL AND METHODS

This study covers the cases and outbreaks of botulism that have been identified and published in any region of Turkey, between 1983 and 2017. This systematic review was performed in accordance with the guidelines for performing and reporting systematic reviews and meta-analyses. The search was done on PubMed and Google in English and Turkish languages. Demographic features of the cases, nutritional sources, the development process of the disease, clinical symptoms and signs, the duration of hospitalization, treatment and mortality rates were analyzed.

RESULTS

Totally 95 patients (57 female and 38 male) were assessed from the published. The food which caused the majority of intoxication cases was canned green beans, and all the foods were home-canned goods. There cords showed that botulism antitoxin was given to 56 patients. The time from exposure to illness onset was 26.9 h. While 18 patients died at the end of follow-up and treatment (mortality 19%), 77 patients were discharged with full recovery.

CONCLUSION

Among 95 botulism cases, spread in Turkey over the last 35 years, the predominant source of toxin was home-canned food and green beans, in particular. Since community and emergency room physicians may be the first to treat patients with any type of botulinum intoxication, they must know how to diagnose and treat this rare but potentially lethal disease.

Development and evaluation of candidate subunit vaccine against botulinum neurotoxin serotype B

Botulinum neurotoxins (BoNTs) are potential biological weapons because of their high toxicity and mortality. Vaccination is an effective strategy to prevent botulism. The carboxyl-terminus of the heavy chain (Hc domain) is nontoxic and sufficient to generate protective immune responses against natural BoNTs in animals. To produce a vaccine suitable for human use, a recombinant non His-tagged isoform of the Hc domain of botulinum neurotoxin serotype B (BHc) was expressed in Escherichia coli and purified by sequential chromatography. The immunogenicity of recombinant E.coli-expressed BHc and the yeast-expressed mBHc antigens was explored and compared in Balb/c mice. BHc provided comparable protective potency but elicited significantly higher antibody titer and neutralization potency against BoNT/B after twice immunization, indicating that the recombinant BHc protein expressed in E.coli have better immunogenicity than the yeast-expressed mBHc. Moreover, a frequency and dose-dependent effect was observed in mice immunized with BHc subunit vaccine and the anti-BHc ELISA antibody titers correlated well with neutralizing antibody titers and protection potency. In summary, the Alhydrogel-formulated BHc subunit vaccine afforded effective protection against BoNT/B challenge. Therefore, the non-His-tagged and homogeneous BHc expressed in E.coli represents a good potential candidate subunit vaccine for human use.

Studying the differential efficacy of postsymptom antitoxin treatment in type A versus type B botulism using a rabbit spirometry model

Botulinum neurotoxin (BoNT) serotypes A, B and E are responsible for most cases of human botulism. The only approved therapy for botulism is antitoxin treatment administered to patients after symptom onset. However, a recent meta-analysis of antitoxin efficacy in human botulism cases over the past century concluded that a statistically significant reduction in mortality is associated with the use of type E and type A antitoxin, but not with type B antitoxin. Animal models could be highly valuable in studying postsymptom antitoxin efficacy (PSAE). However, the few attempts to evaluate PSAE in animals relied on subjective observations and showed ∼50% protection. Recently, we developed a novel spirometry model for the quantitative evaluation of PSAE in rabbits and used it to demonstrate full protection against BoNT/E. In the current study, a comparative evaluation of PSAE in botulism types A and B was conducted using this quantitative respiratory model. A lethal dose of each toxin induced a comparable course of disease both in terms of time to symptoms (TTS, 41.9±1.3 and 40.6±1.1 h, respectively) and of time to death (TTD, 71.3±3.1 and 66.3±1.7 h, respectively). However, in accordance with the differential serotypic PSAE observed in humans, postsymptom antitoxin treatment was fully effective only in BoNT/A-intoxicated rabbits. This serotypic divergence was reflected by a positive and statistically significant correlation between TTS and TTD in BoNT/A-intoxicated rabbits (r=0.91, P=0.0006), but not in those intoxicated with BoNT/B (r=0.06, P=0.88). The rabbit spirometry system might be useful in the evaluation toolkit of botulism therapeutics, including those under development and intended to act when antitoxin is no longer effective.

Summary: Here, we used a quantitative rabbit respiratory model to study the human-related, differential antitoxin efficacy observed in type A and type B botulism.

Phenolic Compounds in Honey and Their Associated Health Benefits: A Review

Honey is a natural substance appreciated for its therapeutic abilities since ancient times. Its content in flavonoids and phenolic acids plays a key role on human health, thanks to the high antioxidant and anti-inflammatory properties that they exert. Honey possesses antimicrobial capacity and anticancer activity against different types of tumors, acting on different molecular pathways that are involved on cellular proliferation. In addition, an antidiabetic activity has also been highlighted, with the reduction of glucose, fructosamine, and glycosylated hemoglobin serum concentration. Honey exerts also a protective effect in the cardiovascular system, where it mainly prevents the oxidation of low-density lipoproteins, in the nervous system, in the respiratory system against asthma and bacterial infections, and in the gastrointestinal system. A beneficial effect of honey can also be demonstrated in athletes. The purpose of this review is to summarize and update the current information regarding the role of honey in health and diseases.

Yesterday and Today: The Impact of Research Conducted at Camp Detrick on Botulinum Toxin

Introduction

This review summarizes the research conducted on botulinum toxin (BoTx) from 1943 to 1956 by a small group of Camp Detrick investigators and their staff. A systematic, cross-disciplinary approach was used to develop effective vaccines against this biological warfare threat agent. In response to the potential need for medical countermeasures against BoTx during World War II, the refinement of isolation and purification techniques for BoTx successfully led to the large-scale production of botulinum toxoid vaccines. In addition, the work at Camp Detrick provided the foundation for the subsequent use of BoTx as a tool for studying the trophic regulation of skeletal muscle within motor neuron terminals and, more recently, for elucidation of the intricate details of neurotransmitter release at the molecular level. Indirectly, Camp Detrick investigators also played a significant role in studies that culminated in the use of BoTx as a pharmaceutical product that has been approved by the U.S. Food and Drug Administration for treating movement disorders, autonomic dysfunctions, and other conditions.

Methods

Online literature searches were performed with Google, Google Scholar, PubMed, the bibliography from the Camp Detrick technical library, and at the Defense Technical Information Center. Reference lists in some of the primary research publications and reviews also provided source material. Search terms included botulinum, botulinus, and Camp Detrick. References related to the subsequent impacts of the Camp Detrick results were selected and cited from reviews and primary references in the more recent literature. Notes on toxin nomenclature and potential sources of error in this study are presented.

Results

The literature searches returned 27 citations of Camp Detrick authors, 24 of which were articles in peer-reviewed journals. The publications by these investigators included several disciplines such as biochemistry, immunology, pharmacology, physiology, and toxicology. A fundamental finding was the identification of critical nutritional components for improved growth of Clostridium botulinum and the increased production of BoTx serotype A. The purification processes that were developed at Camp Detrick allowed for the production of crystalline material to be scaled up for the manufacture of toxoid vaccine. Based on the research by Camp Detrick scientists, a toxoid supply of over 1 million units was available to vaccinate ~300,000 troops before the large-scale operations of D-Day.

Conclusions

BoTx research during the period 1943 to 1956 resulted in refinements in the techniques for isolating and purifying the crystalline BoTx type A. These results led to the development and manufacture of a toxoid vaccine that was available in a sufficient quantity to protect ~300,000 warfighters in a large-scale military operation. One of the most important long-term consequences derived from the knowledge gained by the efforts at Camp Detrick was the development in the 1980s of safe and effective therapeutic uses for BoTx type A, the most lethal biological substance known.

Botulism in pregnancy - a clinical approach to diagnosis and management

Botulism is a life-threatening toxin mediated disease that often presents with a sudden rapid onset of paralysis of their skeletal muscles with subsequent respiratory compromise and sudden death. Given the natural physiological changes during pregnancy, pregnant women with botulism may experience a more exaggerated course and have worse outcomes compared to nonpregnant women. Medical providers caring for such patients should not only maintain a high level of suspicion for botulism, but administration of an antitoxin early in their care can help reduce morbidity and mortality, while awaiting confirmatory laboratory results. It is not uncommon for a medical provider caring for these women to mistakenly associate the signs and symptoms associated with botulism with pregnancy-related findings; therefore, this article illustrates a clinical algorithmic approach to caring for these women, including a systematic approach to establishing a diagnosis and management plan for pregnant women with botulism.

A Novel Rabbit Spirometry Model of Type E Botulism and Its Use for the Evaluation of Postsymptom Antitoxin Efficacy

Botulinum neurotoxins (BoNTs), the most poisonous substances known in nature, pose significant concern to health authorities. The only approved therapeutic for botulism is antitoxin. While administered to patients only after symptom onset, antitoxin efficacy is evaluated in animals mostly in relation to time postintoxication regardless of symptoms. This is most likely due to the difficulty in measuring early symptoms of botulism in animals. In this study, a rabbit spirometry model was developed to quantify early respiratory symptoms of type E botulism that were further used as a trigger for treatment. Impaired respiration, in the form of a reduced minute volume, was detected as early as 18.1 ± 2.9 h after intramuscular exposure to 2 rabbit 50% lethal doses (LD₅₀) of BoNT serotype E (BoNT/E), preceding any visible symptoms. All rabbits treated with antitoxin immediately following symptom onset survived. Postsymptom antitoxin efficacy was further evaluated in relation to toxin and antitoxin dosages as well as delayed antitoxin administration. Our system enabled us to demonstrate, for the first time, full antitoxin protection of animals treated with antitoxin after the onset of objective and quantitative type E botulism symptoms. This model may be utilized to evaluate the efficacy of antitoxins for additional serotypes of BoNT as well as that of next-generation anti-BoNT drugs that enter affected cells and act when antitoxin is no longer effective.

Efficacy of Antitoxin Therapy in Treating Patients With Foodborne Botulism: A Systematic Review and Meta-analysis of Cases, 1923-2016

Background

Botulism is a rare, potentially severe illness, often fatal if not appropriately treated. Data on treatment are sparse. We systematically evaluated the literature on botulinum antitoxin and other treatments.

Methods

We conducted a systematic literature review of published articles in PubMed via Medline, Web of Science, Embase, Ovid, and Cumulative Index to Nursing and Allied Health Literature, and included all studies that reported on the clinical course and treatment for foodborne botulism. Articles were reviewed by 2 independent reviewers and independently abstracted for treatment type and toxin exposure. We conducted a meta-analysis on the effect of timing of antitoxin administration, antitoxin type, and toxin exposure type.

Results

We identified 235 articles that met the inclusion criteria, published between 1923 and 2016. Study quality was variable. Few (27%) case series reported sufficient data for inclusion in meta-analysis. Reduced mortality was associated with any antitoxin treatment (odds ratio [OR], 0.16; 95% confidence interval [CI], .09-.30) and antitoxin treatment within 48 hours of illness onset (OR, 0.12; 95% CI, .03-.41). Data did not allow assessment of critical care impact, including ventilator support, on survival. Therapeutic agents other than antitoxin offered no clear benefit. Patient characteristics did not predict poor outcomes. We did not identify an interval beyond which antitoxin was not beneficial.

Conclusions

Published studies on botulism treatment are relatively sparse and of low quality. Timely administration of antitoxin reduces mortality; despite appropriate treatment with antitoxin, some patients suffer respiratory failure. Prompt antitoxin administration and meticulous intensive care are essential for optimal outcome.

Botulism in Italy, 1986 to 2015

Botulism is a rare but severe neuroparalytic disease caused by botulinum toxins. Because of its high potential impact on public health, botulism is a closely monitored communicable disease in Europe. In Italy, which has one of the highest incidence rates in Europe (0.03 cases per 100,000 population), botulism is monitored through a case-based passive surveillance system: the front-line physician who diagnoses a suspected case must notify the Local Health Units immediately, and the Ministry of Health's office within 12 hours. From 1986 to 2015, 466 confirmed cases of botulism were recorded in Italy (of 1,257 suspected cases). Of these, 421 were food-borne (the most frequently seen form of botulism due to the consumption of improperly home-canned foods), 36 were infant botulism, which accounts for ca 50% of all these types of cases registered in Europe, six were wound-related and three were due to adult intestinal colonisation. This scenario suggests that stronger efforts should be made towards raising public awareness of the risk of food-borne botulism, especially with respect to home-preserved foods, as well as improving the training of front-line medical personnel, to ensure that a quick and accurate diagnosis of botulism can be made.