Development and characterization of a novel neutralizing scFv vectored immunoprophylaxis against botulinum toxin type A

Botulinum toxin is a protein toxin secreted by Clostridium botulinum that is strongly neurotoxic. Due to its characteristics of being super toxic, quick acting, and difficult to prevent, the currently reported antiviral studies focusing on monoclonal antibodies have limited effectiveness. Therefore, for the sake of effectively prevention and treatment of botulism and to maintain country biosecurity as well as the health of the population, in this study, we intend to establish a single chain antibody (scFv) targeting the carboxyl terminal binding functional domain of the botulinum neurotoxin heavy chain (BONT/AHc) of botulinum neurotoxin type A, and explore the value of a new passive immune method in antiviral research which based on adeno-associated virus (AAV) mediated vector immunoprophylaxis (VIP) strategy. The scFv small-molecular single-chain antibody sequenced, designed, constructed, expressed and purified by hybridoma has high neutralising activity and affinity level, which can lay a good foundation for the modification and development of antibody engineering drugs. In vivo experiments, AAV-mediated scFv engineering drug has good anti-BONT/A toxin neutralisation ability, has advantages of simple operation, stable expression and good efficacy, and may be one of the effective treatment strategies for long-term prevention and protection of BONT/A botulinum neurotoxin.

Iatrogenic botulism cases after gastric and axillary application of botulinum toxin and review of literature

INTRODUCTION

Iatrogenic botulism is a rare, serious disease that progresses with descending paralysis and develops after cosmetic or therapeutic botulinum toxin-A (BoNT-A) application.

CASE PRESENTATIONS

In this case series; six cases of iatrogenic botulism followed up in our center are presented. Four of these developed after gastric BoNT-A and two after axillary BoNT-A application.

RESULTS

The most important cause for the disease was the use of unlicensed products and high-dose toxin applications. The first symptoms were blurred vision, double vision, difficulty in swallowing, and hoarseness. Symptoms appeared within 4-10 days after the application of BoNT-A. Symptoms progressed in the course of descending paralysis in the following days with fatigue, weakness in extremities and respiratory distress. Diagnosis was based on patient history and clinical findings. The main principles of foodborne botulism therapy were applied in the treatment of iatrogenic botulism. If clinical worsening continued, regardless of the time elapsed after BoNT-A application, the use of botulinum antitoxin made a significant contribution to clinical improvement and was recommended.

CONCLUSIONS

Routine and new indications for BoNT-A usage are increasing and, as a result, cases of iatrogenic botulism will be encountered more frequently. Physicians should be alert for iatrogenic botulism in the follow-up after BoNT-A applications and in the differential diagnosis of neurological diseases that are presented with similar findings.

Standardization of the Japanese National Standard, Equine Botulinum Antitoxin Type A, and Factors Affecting Standardization

Equine botulinum antitoxin is one of the most popular countermeasures for human botulism. The unitage of the antitoxin product is defined according to national minimum requirement or pharmacopoeia in each country by referring to national standard antitoxins for four types (A, B, E, and F). With the expected depletion of the national standard antitoxins, replacement national standard antitoxins are produced and standardized through collaboration of the National Control Laboratory and other participants, including manufacturer(s). Therefore, Japanese National Standard Botulinum Antitoxin Type A, Equine, was replaced according to the results of a collaborative study involving the National Institute of Infectious Diseases and KM Biologics Co., Ltd. The unitage of the replacement material was determined through mouse neutralization tests, which involved toxin-antitoxin mixture injection at pH 7.0. Potency value of 440 units/vial was obtained. However, the Japanese Minimum Requirement for Biological Products was revised, and the neutralization reactions were repeated at pH 6.0, for which considerably different potency value (656 units/vial) and survival profile of mice were obtained. In September 2021, the replacement material, Japanese National Standard Botulinum Antitoxin Type A, Equine, lot 2, was established with potency value of 656 Units/vial. The impact of pH-dependent change in potency on antitoxin quality control is discussed.

Aminopyridines Restore Ventilation and Reverse Respiratory Acidosis at Late Stages of Botulism in Mice

Botulinum neurotoxin (BoNT) is a potent protein toxin that causes muscle paralysis and death by asphyxiation. Treatments for symptomatic botulism are intubation and supportive care until respiratory function recovers. Aminopyridines have recently emerged as potential treatments for botulism. The clinically approved drug 3,4-diaminopyridine (3,4-DAP) rapidly reverses toxic signs of botulism and has antidotal effects when continuously administered in rodent models of lethal botulism. Although the therapeutic effects of 3,4-DAP likely result from the reversal of diaphragm paralysis, the corresponding effects on respiratory physiology are not understood. Here, we combined unrestrained whole-body plethysmography (UWBP) with arterial blood gas measurements to study the effects of 3,4-DAP, and other aminopyridines, on ventilation and respiration at terminal stages of botulism in mice. Treatment with clinically relevant doses of 3,4-DAP restored ventilation in a dose-dependent manner, producing significant improvements in ventilatory parameters within 10 minutes. Concomitant with improved ventilation, 3,4-DAP treatment reversed botulism-induced respiratory acidosis, restoring blood levels of CO2, pH, and lactate to normal physiologic levels. Having established that 3,4-DAP-mediated improvements in ventilation were directly correlated with improved respiration, we used UWBP to quantitatively evaluate nine additional aminopyridines in BoNT/A-intoxicated mice. Multiple aminopyridines were identified with comparable or enhanced therapeutic efficacies compared with 3,4-DAP, including aminopyridines that selectively improved tidal volume versus respiratory rate and vice versa. In addition to contributing to a growing body of evidence supporting the use of aminopyridines to treat clinical botulism, these data lay the groundwork for the development of aminopyridine derivatives with improved pharmacological properties. SIGNIFICANCE STATEMENT: There is a critical need for fast-acting treatments to reverse respiratory paralysis in patients with botulism. This study used unrestrained, whole-body plethysmography and arterial blood gas analysis to show that aminopyridines rapidly restore ventilation and respiration and reverse respiratory acidosis when administered to mice at terminal stages of botulism. In addition to supporting the use of aminopyridines as first-line treatments for botulism symptoms, these data are expected to contribute to the development of new aminopyridine derivatives with improved pharmacological properties.

Treating rosacea with botulism toxin: Protocol for a systematic review and meta-analysis

BACKGROUND

Rosacea is a chronic inflammatory disease usually associated with persistent erythema and periodic flushing. This disease is difficult to treat, and the outcomes are often unsatisfactory and prone to recurrence. In recent years, botulinum toxin has been used as a new treatment for rosacea; however, its efficacy and safety remain under discussion. Although a systematic review of the effectiveness and safety of botulinum toxin has been previously conducted by other researchers, our systematic review and meta-analysis evaluate the efficacy of botulinum toxin from a more comprehensive and detailed perspective to provide evidence for clinicians.

METHODS

Any study using botulinum toxin for the treatment of rosacea was considered for the analysis.

RESULTS

A total of 22 studies were included, 9 of which were randomized controlled trials involving 720 subjects. After treatment, all studies showed varying degrees of improvement in patient signs and symptoms along with reduced Clinician's Erythema Assessment (CEA) scores. The improvement was maintained for several months, and the adverse effects were mild and self-limiting.

CONCLUSION

Botulinum toxin may be an effective treatment for patients with rosacea; however, further clinical evidence is needed to confirm its long-term efficacy and side effects. The study was preregistered with Prospero (CRD42022358911).

Iatrogenic systemic botulism after intragastric botulinum neurotoxin injection: Case report

BACKGROUND AND PURPOSE

The recent off-label use of botulinum neurotoxin (BoNT) for intragastric obesity treatment has led to 67 cases of systemic botulism in Türkiye, Germany, Austria and Switzerland. This case report highlights the potential risks and adverse effects associated with this treatment.

CASE REPORT

A 36-year-old female presented to the emergency room with shortness of breath, fatigue, difficulty in eating and holding her head, constipation and double vision after receiving intragastric BoNT injection for obesity treatment. She had bilateral orbicularis oculi weakness, facial diplegia, weak tongue, masseter, neck and extremity muscles. Electromyography showed a presynaptic type neuromuscular junction disorder. The patient was admitted to the intensive care unit and administered botulinum heptavalent equine-derived antitoxin, but the medication had to be stopped due to a reaction. The patient was started on pyridostigmine for symptomatic treatment and was transferred to an inpatient clinic after minimal improvement. She was discharged after 7 days of follow-up.

CONCLUSION

Clinicians should be cautious of the potential risks of intragastric BoNT injection for obesity treatment and consider systemic botulism as a potential adverse effect. Antitoxin treatment should be considered in clinically progressing patients despite negative botulinum toxin testing.

Duration of Fecal Excretion of Clostridium Botulinum and Botulinum Neurotoxin in Patients Recovering from Infant Botulism

This study sought to determine duration of fecal excretion of Clostridium botulinum organisms and neurotoxin after onset of infant botulism in 66 affected infants. Median excretion was longer for type A than type B patients (organisms: 5.9 vs 3.5 weeks, toxin: 4.8 vs 1.6 weeks, respectively). Toxin excretion always ceased before organism excretion. Antibiotic therapy did not affect duration of excretion.

Iatrogenic Botulism: A Case Treated With Botulinum Antitoxin

OBJECTIVE

Botulinum toxin type A is widely used for the treatment of spasticity, focal dystonia, hemifacial spasm, hyperhidrosis, strabismus, chronic migraine, and also cosmetic purposes. Therapeutic use is commonly effective and safe. However, if toxin enters the vascular space and gets through to peripheral cholinergic nerve terminals, it may lead to iatrogenic botulism.

METHOD

We presented a patient who is diagnosed as iatrogenic botulism and treated with antitoxin at the 15th day of the exposure.

RESULTS

After the antitoxin administration, dramatical response to the treatment was observed.

CONCLUSIONS

In this report, we want to evaluate a new case of iatrogenic botulism and emphasize the importance of antitoxin administration regardless the timing of the exposure for patients with progressing paralysis.

Botulism in Spain: Epidemiology and Outcomes of Antitoxin Treatment, 1997-2019

BACKGROUND

Botulism is a low incidence but potentially fatal infectious disease caused by neurotoxins produced mainly by Clostridium botulinum. There are different routes of acquisition, food-borne and infant/intestinal being the most frequent presentation, and antitoxin is the treatment of choice in all cases. In Spain, botulism is under surveillance, and case reporting is mandatory.

METHODS

This retrospective study attempts to provide a more complete picture of the epidemiology of botulism in Spain from 1997 to 2019 and an assessment of the treatment, including the relationship between a delay in antitoxin administration and the length of hospitalization using the Cox proportional hazards test and Kruskal-Wallis test, and an approach to the frequency of adverse events, issues for which no previous national data have been published.

RESULTS

Eight of the 44 outbreaks were associated with contaminated commercial foods involving ≤7 cases/outbreak; preserved vegetables were the main source of infection, followed by fish products; early antitoxin administration significantly reduces the hospital stay, and adverse reactions to the antitoxin affect around 3% of treated cases.

Investigation of Salicylanilides as Botulinum Toxin Antagonists

Botulinum neurotoxin serotype A (BoNT/A) is recognized by the Centers for Disease Control and Prevention (CDC) as the most potent toxin and as a Tier 1 biowarfare agent. The severity and longevity of botulism stemming from BoNT/A is of significant therapeutic concern, and early administration of antitoxin-antibody therapy is the only approved pharmaceutical treatment for botulism. Small molecule therapeutic strategies have targeted both the heavy chain (HC) and the light chain (LC) catalytic active site and α-/β-exosites. The LC translocation mechanism has also been studied, but an effective, nontoxic inhibitor remains underexplored. In this work, we screened a library of salicylanilides as potential translocation inhibitors. Potential leads following a primary screen were further scrutinized to identify sal30, which has a cellular minimal concentration of a drug that is required for 50% inhibition (IC50) value of 141 nM. The inquiry of salicylanilide sal30's mechanism of action was explored through a self-quenched fluorogenic substrate conjugated to bovine serum albumin (DQ-BSA) fluorescence, confocal microscopy, and vacuolar H+-ATPase (V-ATPase) inhibition assays. The summation of these findings imply that endolysosomal proton translocation through the protonophore mechanism of sal30 causes endosome pH to increase, which in turn prevents LC translocation into cytosol, a process that requires an acidic pH. Thus, the inhibition of BoNT/A activity by salicylanilides likely occurs through disruption of pH-dependent endosomal LC translocation. We further probed BoNT inhibition by sal30 using additivity analysis studies with bafilomycin A1, a known BoNT/A LC translocation inhibitor, which indicated the absence of synergy between the two ionophores.

[Iatrogenic botulism in therapeutic use of botulinum toxin]

The review summarises the current knowledge of the treatment of iatrogenic botulinum toxin overdose. The symptoms may be diffuse, and suspicion should be raised based on time of symptom appearance relative to the time of exposure. Iatrogenic botulism may appear if the maximum recommended total dose of botulinum toxin has been exceeded and if the drug is spread locally from the site of injection or is redistributed to the systemic circulation. The adverse drug reactions frequency is possibly underreported. Fast initiation of the available antidote may be needed. The guideline provided on treatment of iatrogenic botulism is developed from non-iatrogenic botulism.

Outbreak of foodborne botulism in Alexandria, Egypt: modulating indications for administration of heptavalent botulinum antitoxin

In October 2019, ninety-four patients were admitted into Alexandria Poison Center (APC) with a history of ingestion of Feseekh (salted fish). In an attempt to allocate the resources, not all patients were given HBAT (botulism antitoxin heptavalent (A, B, C, D, E, F, G) equine immediately. The current study aimed to portray the clinical characteristics of the cases, explore the possible relation between these characteristics and necessity of HBAT administration, explore the reliability of mouse lethal test, and establish a clinical guide for management including preservation of resources. The current prospective study included 94 patients who were admitted to Alexandria Poison Center (APC) in the period from the 29^th of September to the 27^th of October 2019. The patients' data were recorded using a checklist that includes: personal data, past medical history, clinical assessment, investigations, treatment, and the outcome. The checklist was carried out to assess and follow up each patient. Hospitalized patients were categorized according to symptoms consistent with botulism. The equine HBAT, made by Emergent BioSolutions Canada Inc. (formerly Cangene Corporation), was used in the treatment. HBAT was given to thirty-four patients (36.2%) only out of the total admission. However, eighty-two (87.2%) of patients were completely cured, whereas ten patients (10.6%) were discharged with mild neurological sequels and death occurred only in two cases (2.2%). Sixty cases (63.8%) with suspected foodborne botulism could be managed by supportive treatment only with no need for HBAT, while patients with evident neurological signs received HBAT immediately.

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.

Safety verification for polysorbate 20, pharmaceutical excipient for intramuscular administration, in Sprague-Dawley rats and New Zealand White rabbits

Human serum albumin (HSA) has been widely used as a pharmaceutical excipient in Botulinum toxin serotype A (BoNT/A) products that are indicated for use in therapeutics and cosmetics. However, HSA as a human-derived material has some concerns, such as the potential risk of transmission of infectious agents, an insufficient supply, and difficulty in maintaining a certain quality. For those reasons, newly developed BoNT/A products (CORETOX^®, Medytox, Inc., Republic of Korea) contained polysorbate 20, a non-human-derived excipient, to replace the HSA. However, most safety studies of polysorbate 20 have been conducted with non-invasive routes of administration, and thus there are a few studies on the safety of polysorbate 20 when administered intramuscularly. To secure the in vivo safety profile of polysorbate 20, a four-week repeated intramuscular dose toxicity study (0.02, 0.1, and 0.4 mg/kg, one injection every two weeks for a total of three injections) was conducted in 66 Sprague-Dawley (SD) rats. An intradermal irritation study was further conducted with 18 New Zealand White (NZW) rabbits. The toxicological evaluation of HSA (0.06 and 0.12 mg/kg) was also carried out as a comparative substance. Systemic and local toxicities were not observed in any of the SD rats or NZW rabbits based on clinical signs, body weight, hematology, clinical biochemistry, macroscopic findings on necropsy, histopathology of the injection site, and allergic reactions. The current study suggested that intramuscular administration of polysorbate 20 was considered to be safe at a level similar to that of HSA, which has an in vivo safety profile accumulated over the years. This provided the basis for the in vivo safety profile of polysorbate 20 administered intramuscularly and the scientific reliability of the use of polysorbate 20 as an alternative to HSA, which is used as an excipient for various pharmaceuticals in terms of its safety.

Neuronal delivery of antibodies has therapeutic effects in animal models of botulism

Botulism is caused by a potent neurotoxin that blocks neuromuscular transmission, resulting in death by asphyxiation. Currently, the therapeutic options are limited and there is no antidote. Here, we harness the structural and trafficking properties of an atoxic derivative of botulinum neurotoxin (BoNT) to transport a function-blocking single-domain antibody into the neuronal cytosol where it can inhibit BoNT serotype A (BoNT/A1) molecular toxicity. Post-symptomatic treatment relieved toxic signs of botulism and rescued mice, guinea pigs, and nonhuman primates after lethal BoNT/A1 challenge. These data demonstrate that atoxic BoNT derivatives can be harnessed to deliver therapeutic protein moieties to the neuronal cytoplasm where they bind and neutralize intracellular targets in experimental models. The generalizability of this platform might enable delivery of antibodies and other protein-based therapeutics to previously inaccessible intraneuronal targets.

Two Cases of Infant Botulism Presenting with Altered Mental Status

Infant botulism is a progressive process described as starting with descending weakness, facial palsies and constipation. Loss of bulbar reflexes and flaccid paralysis are common in infants less than 6 months old who have infant botulism. Clostridium botulinum, the bacteria that produce the toxin that causes this condition, are ubiquitous in the United States including Hawai'i, but infant botulism is rarely reported here. This report describes 2 cases of infant botulism with atypical initial presentations diagnosed on O'ahu, Hawai'i. Patient A is a 3-month-old male who presented with altered mental status, including inconsolability, who progressed to loss of gag reflex and constipation. Due to early concern for meningitis, Patient A was treated with antibiotics, however further evaluation led to eventual positive testing for botulinum B toxin. Patient B is a 2-month-old female who presented with somnolence and fever after immunizations and progressed to respiratory failure and apparent dehydration. Because she presented shortly after receiving immunizations, metabolic disorders were strongly considered as a potential cause of symptoms, but Patient B had normal metabolic evaluation and eventually tested positive for botulinum A toxin. Altered mental status and fever are unusual presentations for infant botulism. Infant botulism should be considered in infants with altered mental status when the course of illness includes the development of constipation and weakness, and evaluations are not suggestive of alternative causes, including infection, metabolic diseases, and spinal muscular atrophy. Early consideration and treatment of infant botulism should be considered for infants presenting with altered mental status who develop neuromuscular weakness. The Infant Botulism Treatment and Prevention Program (www.infantbotulism.org) should be contacted early for assistance with diagnosis and treatment.

Lambert-Eaton Myasthenic Syndrome, Botulism, and Immune Checkpoint Inhibitor-Related Myasthenia Gravis

PURPOSE OF REVIEW

This article reviews the pathophysiology, epidemiology, clinical presentation, diagnosis, and treatment of Lambert-Eaton myasthenic syndrome (LEMS) and of botulism, and immune-related myasthenia gravis (MG) occurring in the context of immune checkpoint inhibitor therapy for cancer.

RECENT FINDINGS

The suspicion that LEMS is rare but also likely underdiagnosed is supported by recent epidemiologic data. A validated, LEMS-specific scale now exists to assess and monitor disease, and symptomatic and immunomodulatory treatments are available. As presynaptic disorders of neuromuscular transmission, LEMS and botulism share electrodiagnostic abnormalities but have important distinguishing features. Knowledge of the clinical features of botulism is needed, particularly with continued cases of infant botulism, the opioid epidemic increasing the incidence of wound botulism, and medical use of botulinum toxin, which may cause iatrogenic botulism. Foodborne botulism remains rare. Prompt recognition of botulism and administration of antitoxin can improve outcomes. MG may be exacerbated or may present de novo in the context of immune activation from immune checkpoint inhibitor therapies for cancer. Immune-related MG commonly overlaps with myositis and myocarditis. Corticosteroids typically result in improvement. However, immune-related MG can be more fulminant than its idiopathic counterpart and may cause permanent disability or death.

SUMMARY

The diagnosis of LEMS, botulism, or immune-related MG can generally be made from the patient's history, supplemented with directed questions, a physical examination designed to demonstrate abnormalities, and laboratory and electrodiagnostic testing. Early diagnosis and carefully selected treatment not only improve outcomes of the neuromuscular disease but can affect the prognosis of underlying malignancy, when present.

Symptomatic treatment of botulism with a clinically approved small molecule

Botulinum neurotoxins (BoNTs) are potent neuroparalytic toxins that cause mortality through respiratory paralysis. The approved medical countermeasure for BoNT poisoning is infusion of antitoxin immunoglobulins. However, antitoxins have poor therapeutic efficacy in symptomatic patients; thus, there is an urgent need for treatments that reduce the need for artificial ventilation. We report that the US Food and Drug Administration-approved potassium channel blocker 3,4-diaminopyridine (3,4-DAP) reverses respiratory depression and neuromuscular weakness in murine models of acute and chronic botulism. In ex vivo studies, 3,4-DAP restored end-plate potentials and twitch contractions of diaphragms isolated from mice at terminal stages of BoNT serotype A (BoNT/A) botulism. In vivo, human-equivalent doses of 3,4-DAP reversed signs of severe respiratory depression and restored mobility in BoNT/A-intoxicated mice at terminal stages of respiratory collapse. Multiple-dosing administration of 3,4-DAP improved respiration and extended survival at up to 5 LD50 BoNT/A. Finally, 3,4-DAP reduced gastrocnemius muscle paralysis and reversed respiratory depression in sublethal models of serotype A-, B-, and E-induced botulism. These findings make a compelling argument for repurposing 3,4-DAP to symptomatically treat symptoms of muscle paralysis caused by botulism, independent of serotype. Furthermore, they suggest that 3,4-DAP is effective for a range of botulism symptoms at clinically relevant time points.

Cost savings associated with timely treatment of botulism with botulism antitoxin heptavalent product

Background

Botulism is a rare, serious, and sometimes fatal paralytic illness caused by exposure to neurotoxins produced by Clostridium botulinum bacteria. Patients with documented or suspected exposure to botulinum toxin serotypes A-G can be treated with BAT^® [Botulism Antitoxin Heptavalent (A, B, C, D, E, F, G)–(Equine)] product, which was approved in 2013 in the United States (US). Patients with botulism have demonstrated greater clinical benefit with early BAT product treatment (≤2 days from symptom onset) versus late treatment (>2 days).

Objective

Economic outcomes associated with improved clinical outcome benefits of BAT product treatment have not yet been reported. This ad hoc analysis aimed to estimate and compare costs associated with hospitalization, intensive care unit stay, and mechanical ventilation for patients with botulism administered BAT product treatment early or late.

Methods

Clinical outcomes data for early and late BAT product treatment were obtained from a patient registry conducted between October 2014 and July 2017. Total per patient mean daily costs were estimated based on information from published literature. Total population costs per group were calculated by multiplying estimated mean cost per patient by the average annual number of non-infant botulism cases in the US.

Results

Mean per patient costs were 2.5 times lower for patients treated with BAT product early versus late. On average in the US, early BAT product treatment could save greater than $3.9 million per year versus late treatment.

Conclusion

Substantial economic savings can be achieved with early BAT product treatment. The findings support the recommendation for public health authorities to ensure antitoxin treatment is readily available in sufficient quantities to manage botulism cases, including sporadic outbreaks and potential mass exposure biological attacks.

Efficacy of equine botulism antitoxin in botulism poisoning in a guinea pig model

Background

Botulism is a disease caused by neurogenic toxins that block acetylcholine release, resulting in potentially life threatening neuroparalysis. Seven distinct serotypes of botulinum neurotoxins (BoNTs) have been described and are found in nature world-wide. This, combined with ease of production, make BoNTs a significant bioweapon threat. An essential countermeasure to this threat is an antitoxin to remove circulating toxin. An antitoxin, tradename BAT (Botulism Antitoxin Heptavalent (A, B, C, D, E, F, G)–(Equine)), has been developed and its efficacy evaluated against all seven serotypes in guinea pigs.

Methods and findings

Studies were conducted to establish the lethal dose and clinical course of intoxication for all seven toxins, and post-exposure prophylactic efficacy of BAT product. Animals were monitored for signs of intoxication and mortality for 14 days. Guinea pig intramuscular LD_50s (GPIMLD₅₀) for all BoNTs ranged from 2.0 (serotype C) to 73.2 (serotype E) of mouse intraperitoneal LD₅₀ units. A dose of 4x GPIMLD₅₀ was identified as the appropriate toxin dose for use in subsequent efficacy and post-exposure prophylaxis studies. The main clinical signs observed included hind limb paralysis, weak limb, change in breathing rate/pattern, and forced abdominal respiration. Mean time to onset of clinical signs ranged from 12 hours (serotype E) to 39 hours (serotype G). Twelve hours post-intoxication was selected as the appropriate time point for intervention for all serotypes apart from E where 6 hours was selected because of the rapid onset and progression of clinical signs. Post-exposure treatment with BAT product resulted in a significantly (p<0.0001) higher survival at >0.008 scaled human dose for serotypes A, B, C, F and G, at >0.2x for serotype D and >0.04x for serotype E.

Conclusions

These studies confirm the efficacy of BAT as a post-exposure prophylactic therapy against all seven known BoNT serotypes.

Botulism - a rare but still present, life-threatening disease

Botulism caused by toxins of Clostridium botulinum and other neurotoxic clostridia is a rare but life-threatening disease with neurological symptoms. Food-borne botulism (food poisoning) is the most common type worldwide; rarely, wound botulism, infant botulism, or botulism of unknown etiology may also occur. Botulism is a very rare disease in the Czech Republic as well, with only nine cases reported since 2008 (EPIDAT). These were mostly sporadic cases of food-borne botulism except a small family outbreak with three cases due to the consumption of homemade pork pate (2013). This outbreak prompted the creation of a national standby supply of life-saving anti-infective drugs in Prague. This article reviews the etiology, epidemiology, clinical manifestations, diagnosis, and therapy of botulism.

[Foodbourne Botulism: A Forgotten Disease]

Botulism is a serious illness caused by exposure to botulinum toxin. It is manifested by flaccid, paralysis, symmetric and in descending pattern affecting cranial and peripheral nerves. Given the frequent need for invasive mechanical ventilation, these patients should be approached in an intensive care setting. Treatment with anti-botulinum toxin is the only effective treatment. The authors present the case of a 64-year-old patient, with vomiting and vertigo, evolution to diplopia, dysphagia and flaccid, muscle paralysis, installation after ingestion of canning homemade. From the etiologica, we highlight the electroneuromyogram study with a pre-synaptic lesion compatible with the botulism hypothesis. Progressive improvement of the deficits after administration of anti-botulinum toxin. A brief theoretical review is made of a serious, potentially fatal and infrequent pathology in our country.

[Toxin-infections and toxin-related diseases due to Clostridia other than Clostridium difficile]

Clostridia cause severe diseases. Tetanus is rare in Switzerland because of vaccine coverage and the application of guidelines for the management of contaminated wounds. Tetanus requires wound debridement and the administration of antibiotics and anti-tetanus immune. Besides gastroenteritis, infections due to C. perfringens most often require surgery, in addition to antibiotic treatment with penicillin and clindamycin. Botulism is a rare disease caused by a toxin produced by C. botulinum that causes flaccid paralysis. The clinical syndrome must be recognized early in order to administer the antitoxin and improve the prognosis. The other, rarer species of Clostridia require surgical and antibiotic management, but their prognosis remains poor.

Clinical analysis of 86 botulism cases caused by cosmetic injection of botulinum toxin (BoNT)

This study was conducted to analyze the clinical characteristics of and treatment strategies for botulism among patients receiving cosmetic injection of botulinum toxin (BoNT).A total of 86 botulism patients caused by cosmetic injection of BoNT were enrolled in our study. All of the patients were diagnosed according to their history of cosmetic BoNT injection, clinical symptoms and signs, and other auxiliary examinations (including those on renal and liver functions, blood index detection, and chest X-ray). All of the patients received comprehensive treatments and botulinum antitoxin serum injection.The main symptoms of botulism patients included headache, dizziness, insomnia, fatigue, blurred vision, eye opening difficulty, slurred speech, dysphagia, bucking, constipation, and anxiety. These clinical symptoms occurred 0∼36 days after BoNT injection, especially from 2nd to 6th day after the operation. Furthermore, the usage dose of BoNT was negatively related to latent period. Finally, patients all discharged from our hospital 1∼20 days after treatments, and their symptoms relieved or disappeared.Botulism is a severe side effect for BoNT injection. Injecting botulinum antitoxin serum may be an effective approach to improve clinical outcomes of botulism cases.

An ambient temperature-stable antitoxin of nine co-formulated antibodies for botulism caused by serotypes A, B and E

Safe and effective antitoxins to treat and prevent botulism are needed for biodefense. We have developed recombinant antibody-based therapeutics for botulinum neurotoxin (BoNT) serotypes A, B, and E. The mechanism of action of this antitoxin requires that three mAbs bind one toxin molecule to achieve clearance. Here we present a co-formulation of an antitoxin to the three most important serotypes. Combining these antibodies obviates the need to identify the serotype causing intoxication prior to drug administration, which would facilitate administration. The lyophilized powder formulation contains nine mAbs, three mAbs for each of the three serotypes (A, B, E). The formulation was stored as a liquid and lyophilized powder for up to one year, and characterized by binding affinity and multiple physicochemical methods. No significant increase in soluble higher order aggregates, cleavage products, or change in charge isoforms was measured after storage as a lyophilized powder at 50°C for one year. Furthermore, toxin-domain binding ELISA data indicated that each of the individual antibodies in the lyophilized drug product showed essentially full binding capability to their respective toxin domains after being stored at 50°C for one year. Physicochemical characterization of the formulation demonstrated the nine individual mAbs were remarkably stable. This work demonstrates feasibility of lyophilized, oligoclonal antibody therapies for biodefense with ambient temperature stability, that would facilitate stockpiling, distribution, and administration.

Workgroup Report by the Joint Task Force Involving American Academy of Allergy, Asthma & Immunology (AAAAI); Food Allergy, Anaphylaxis, Dermatology and Drug Allergy (FADDA) (Adverse Reactions to Foods Committee and Adverse Reactions to Drugs, Biologicals, and Latex Committee); and the Centers for Disease Control and Prevention Botulism Clinical Treatment Guidelines Workgroup-Allergic Reactions to Botulinum Antitoxin: A Systematic Review

Background

Naturally occurring botulism is rare, but a large number of cases could result from unintentional or intentional contamination of a commercial food. Despeciated, equine-derived, heptavalent botulinum antitoxin (HBAT) is licensed in the United States. Timely treatment reduces morbidity and mortality, but concerns that botulinum antitoxin can induce anaphylaxis exist. We sought to quantify the allergy risk of botulinum antitoxin treatment and the usefulness of skin testing to assess this risk.

Methods

We conducted a systematic review of (1) allergic reactions to botulinum antitoxin and (2) the predictive value of skin testing (ST) before botulinum antitoxin administration. We searched 5 scientific literature databases, reviewed articles' references, and obtained data from the HBAT manufacturer and from the Centers for Disease Control and Prevention. Anaphylaxis incidence was determined for HBAT and previously employed botulinum antitoxins. We calculated the positive predictive value (PPV) and negative predictive value (NPV) of ST for anaphylaxis related to HBAT and other botulinum antitoxins.

Results

Seven articles were included. Anaphylaxis incidence was 1.64% (5/305 patients) for HBAT and 1.16% (8/687 patients) for all other botulinum antitoxins (relative risk, 1.41 [95% confidence interval, .47-4.27]; P = .5). Observed values for both PPV and NPV for HBAT-ST (33 patients) were 100%. Observed PPVs and NPVs of ST for other botulinum antitoxins (302 patients) were 0-56% and 50%-100%, respectively. There were no reports of fatal anaphylaxis.

Conclusions

Considering the <2 % rate of anaphylaxis, fatal outcomes, modest predictive value of ST, resource requirements for ST, and the benefits of early treatment, data do not support delaying HBAT administration to perform ST in a mass botulinum toxin exposure. Anaphylactic reactions may occur among 1%-2% of botulinum antitoxin recipients and will require epinephrine and antihistamine treatment and, possibly, intensive care.

[Clostridia: toxin masters. Botulism: from botox to sausages?]

Clostridia are ubiquitous Gram-positive bacteria whose toxins are responsible for serious diseases. In this article we report a case of foodborne botulism we have recently managed. Moreover, we briefly describe the major clinical syndromes caused by different species of Clostridium (except for C. difficile infections, as this subject has been previously extensively reviewed in this journal). Botulism causes a flaccid paralysis starting with cranial nerves. Administration of botulism anti-toxin should be rapidly considered as soon as botulism is suspected, as prognosis is largely dependent on timely treatment; alerting the public health authorities is equally important. In Switzerland botulinum antitoxin can be obtained from the pharmacy of the Swiss Army.

Development of Human-Like scFv-Fc Neutralizing Botulinum Neurotoxin E

Background

Botulinum neurotoxins (BoNTs) are considered to be the most toxic substances known on earth and are responsible for human botulism, a life-threatening disease characterized by flaccid muscle paralysis that occurs naturally by food-poisoning or colonization of the gastrointestinal tract by BoNT-producing clostridia. BoNTs have been classified as category A agent by the Centers of Disease Control and Prevention (CDC) and are listed among the six agents with the highest risk to be used as bioweapons. Neutralizing antibodies are required for the development of effective anti-botulism therapies to deal with the potential risk of exposure.

Results

In this study, a macaque (Macaca fascicularis) was immunized with recombinant light chain of BoNT/E3 and an immune phage display library was constructed. After a multi-step panning, several antibody fragments (scFv, single chain fragment variable) with nanomolar affinities were isolated, that inhibited the endopeptidase activity of pure BoNT/E3 in vitro by targeting its light chain. Furthermore, three scFv were confirmed to neutralize BoNT/E3 induced paralysis in an ex vivo mouse phrenic nerve-hemidiaphragm assay. The most effective neutralization (20LD₅₀/mL, BoNT/E3) was observed with scFv ELC18, with a minimum neutralizing concentration at 0.3 nM. Furthermore, ELC18 was highly effective in vivo when administered as an scFv-Fc construct. Complete protection of 1LD₅₀ BoNT/E3 was observed with 1.6 ng/dose in the mouse flaccid paralysis assay.

Conclusion

These scFv-Fcs antibodies are the first recombinant antibodies neutralizing BoNT/E by targeting its light chain. The human-like nature of the isolated antibodies is predicting a good tolerance for further clinical development.

[Infant botulism]

Infant botulism is a paralytic syndrome which manifests as a result of ingesting spores of the toxin secreting bacterium Clostridium botulinum by infants. As opposed to botulism in adults, treating infant botulism with horse antiserum was not approved due to several safety issues. This restriction has led to the development of Human Botulism Immune Globulin Intravenous (BIG-IV; sells under BabyBIG). In this article we review infant botulism and the advantages of treating it with BIG-IV.

Sheep monoclonal antibodies prevent systemic effects of botulinum neurotoxin A1

Botulinum neurotoxin (BoNT) is responsible for causing botulism, a potentially fatal disease characterized by paralysis of skeletal muscle. Existing specific treatments include polyclonal antisera derived from immunized humans or horses. Both preparations have similar drawbacks, including limited supply, risk of adverse effects and batch to batch variation. Here, we describe a panel of six highly protective sheep monoclonal antibodies (SMAbs) derived from sheep immunized with BoNT/A1 toxoid (SMAbs 2G11, 4F7) or BoNT/A1 heavy chain C-terminus (HcC) (SMAbs 1G4, 5E2, 5F7, 16F9) with or without subsequent challenge immunization with BoNT/A1 toxin. Although each SMAb bound BoNT/A1 toxin, differences in specificity for native and recombinant constituents of BoNT/A1 were observed. Structural differences were suggested by pI (5E2 = 8.2; 2G11 = 7.1; 4F7 = 8.8; 1G4 = 7.4; 5F7 = 8.0; 16F9 = 5.1). SMAb protective efficacy vs. 10,000 LD50 BoNT/A1 was evaluated using the mouse lethality assay. Although not protective alone, divalent and trivalent combinations of SMabs, IG4, 5F7 and/or 16F9 were highly protective. Divalent combinations containing 0.5–4 μg/SMAb (1–8 μg total SMAb) were 100% protective against death with only mild signs of botulism observed; relative efficacy of each combination was 1G4 + 5F7 > 1G4 + 16F9 >> 5F7 + 16F9. The trivalent combination of 1G4 + 5F7 + 16F9 at 0.25 μg/SMAb (0.75 μg total SMAb) was 100% protective against clinical signs and death. These results reflect levels of protective potency not reported previously.

Small-molecule quinolinol inhibitor identified provides protection against BoNT/A in mice

Botulinum neurotoxins (BoNTs), etiological agents of the life threatening neuroparalytic disease botulism, are the most toxic substances currently known. The potential for the use as bioweapon makes the development of small-molecule inhibitor against these deadly toxins is a top priority. Currently, there are no approved pharmacological treatments for BoNT intoxication. Although an effective vaccine/immunotherapy is available for immuno-prophylaxis but this cannot reverse the effects of toxin inside neurons. A small-molecule pharmacological intervention, especially one that would be effective against the light chain protease, would be highly desirable. Similarity search was carried out from ChemBridge and NSC libraries to the hit (7-(phenyl(8-quinolinylamino)methyl)-8-quinolinol; NSC 84096) to mine its analogs. Several hits obtained were screened for in silico inhibition using AutoDock 4.1 and 19 new molecules selected based on binding energy and Ki. Among these, eleven quinolinol derivatives potently inhibited in vitro endopeptidase activity of botulinum neurotoxin type A light chain (rBoNT/A-LC) on synaptosomes isolated from rat brain which simulate the in vivo system. Five of these inhibitor molecules exhibited IC(50) values ranging from 3.0 nM to 10.0 µM. NSC 84087 is the most potent inhibitor reported so far, found to be a promising lead for therapeutic development, as it exhibits no toxicity, and is able to protect animals from pre and post challenge of botulinum neurotoxin type A (BoNT/A).

[Botulism]

Botulism is a rare but potentially life-threatening disease caused by Clostridium botulinum neurotoxin. In Finland only a few cases have been diagnosed during the past ten years but mild cases may be underdiagnosed. The diagnosis of botulism is clinical. Patients present with weakness in muscles innervated by the cranial nerves. In more severe cases the paralysis gradually progresses in a descending order and may affect respiratory muscles leading to mechanical ventilation. Routine laboratory tests or radiology are unhelpful in initial diagnostics. A practicing physician should administrate botulinum antitoxin immediately when food-borne botulism is suspected since it may be life-saving.

The anti-botulism triterpenoid toosendanin elicits calcium increase and exocytosis in rat sensory neurons

Toosendanin, a triterpenoid from Melia toosendan Sieb et Zucc, has been found before to be an effective anti-botulism agent, with a bi-phasic effect at both motor nerve endings and central synapse: an initial facilitation followed by prolonged depression. Initial facilitation may be due to activation of voltage-dependent calcium channels plus inhibition of potassium channels, but the depression is not fully understood. Toosendanin has no effect on intracellular calcium or secretion in the non-excitable pancreatic acinar cells, ruling out general toosendanin inhibition of exocytosis. In this study, toosendanin effects on sensory neurons isolated from rat nodose ganglia were investigated. It was found that toosendanin stimulated increases in cytosolic calcium and neuronal exocytosis dose dependently. Experiments with membrane potential indicator bis-(1,3-dibutylbarbituric acid)trimethine oxonol found that toosendanin hyperpolarized capsaicin-insensitive but depolarized capsaicin-sensitive neurons; high potassium-induced calcium increase was much smaller in hyperpolarizing neurons than in depolarizing neurons, whereas no difference was found for potassium-induced depolarization in these two types of neurons. In neurons showing spontaneous calcium oscillations, toosendanin increased the oscillatory amplitude but not frequency. Toosendanin-induced calcium increase was decreased in calcium-free buffer, by nifedipine, and by transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine. Simultaneous measurements of cytosolic and endoplasmic reticulum (ER) calcium showed an increase in cytosolic but a decrease in ER calcium, indicating that toosendanin triggered ER calcium release. These data together indicate that toosendanin modulates sensory neurons, but had opposite effects on membrane potential depending on the presence or absence of capsaicin receptor/TRPV 1 channel.

Equine botulinum antitoxin for the treatment of infant botulism

Infant botulism is the most common form of human botulism in Argentina and the United States. BabyBIG (botulism immune globulin intravenous [human]) is the antitoxin of choice for specific treatment of infant botulism in the United States. However, its high cost limits its use in many countries. We report here the effectiveness and safety of equine botulinum antitoxin (EqBA) as an alternative treatment. We conducted an analytical, observational, retrospective, and longitudinal study on cases of infant botulism registered in Mendoza, Argentina, from 1993 to 2007. We analyzed 92 medical records of laboratory-confirmed cases and evaluated the safety and efficacy of treatment with EqBA. Forty-nine laboratory-confirmed cases of infant botulism demanding admission in intensive care units and mechanical ventilation included 31 treated with EqBA within the 5 days after the onset of signs and 18 untreated with EqBA. EqBA-treated patients had a reduction in the mean length of hospital stay of 23.9 days (P = 0.0007). For infants treated with EqBA, the intensive care unit stay was shortened by 11.2 days (P = 0.0036), mechanical ventilation was reduced by 11.1 days (P = 0.0155), and tube feeding was reduced by 24.4 days (P = 0.0001). The incidence of sepsis in EqBA-treated patients was 47.3% lower (P = 0.0017) than in the untreated ones. Neither sequelae nor adverse effects attributable to EqBA were noticed, except for one infant who developed a transient erythematous rash. These results suggest that prompt treatment of infant botulism with EqBA is safe and effective and that EqBA could be considered an alternative specific treatment for infant botulism when BabyBIG is not available.

Centers for Disease Control and Prevention (CDC). Notes from the field: Botulism caused by consumption of commercially produced potato soups stored improperly--Ohio and Georgia, 2011

In January and April 2011, CDC provided antitoxin for treatment of two persons with toxin type A botulism associated with consumption of potato soup produced by two companies. On January 28, 2011, an Ohio resident, aged 29 years, was hospitalized after 5 days of progressive dizziness, blurred vision, dysphagia, and difficulty breathing. The patient required mechanical ventilation and botulism antitoxin. On January 18, he had tasted potato soup from a bulging plastic container, noted a bad taste, and discarded the remainder. The soup had been purchased on December 7, 2010, from the refrigerated section of a local grocer, but it had been kept unrefrigerated for 42 days. He was hospitalized for 57 days and then was transferred with residual weakness to a rehabilitation facility.

Botulinum neurotoxins and botulism: a novel therapeutic approach

Specific treatment is not available for human botulism. Current remedial mainstay is the passive administration of polyclonal antibody to botulinum neurotoxin (BoNT) derived from heterologous species (immunized animal or mouse hybridoma) together with supportive and symptomatic management. The antibody works extracellularly, probably by blocking the binding of receptor binding (R) domain to the neuronal receptors; thus inhibiting cellular entry of the holo-BoNT. The antibody cannot neutralize the intracellular toxin. Moreover, a conventional antibody with relatively large molecular size (150 kDa) is not accessible to the enzymatic groove and, thus, cannot directly inhibit the BoNT zinc metalloprotease activity. Recently, a 15-20 kDa single domain antibody (V(H)H) that binds specifically to light chain of BoNT serotype A was produced from a humanized-camel VH/V(H)H phage display library. The V(H)H has high sequence homology (>80%) to the human VH and could block the enzymatic activity of the BoNT. Molecular docking revealed not only the interface binding between the V(H)H and the toxin but also an insertion of the V(H)H CDR3 into the toxin enzymatic pocket. It is envisaged that, by molecular linking the V(H)H to a cell penetrating peptide (CPP), the CPP-V(H)H fusion protein would be able to traverse the hydrophobic cell membrane into the cytoplasm and inhibit the intracellular BoNT. This presents a novel and safe immunotherapeutic strategy for botulism by using a cell penetrating, humanized-single domain antibody that inhibits the BoNT by means of a direct blockade of the groove of the menace enzyme.

[Botulism in an infant]

We describe a case of botulism in a 4.5 month-old girl with complete recovery after intravenous administration of botulism immune globulin. The girl was admitted for 19 days during which supplementary nasogastric feeding was necessary. Mechanical ventilation was not needed. Despite thorough investigation, contaminated food was not found. One particular batch of canned baby food was suspected and recalled from the market, but no contamination was found. The girl had not ingested honey. The condition is rare, but can be very serious and should be kept in mind in cases presenting with the well-defined symptoms of the condition.

Cluster of botulism among Dutch tourists in Turkey, June 2008

In June 2008, three Dutch tourists participating in a mini-cruise in Turkey needed urgent repatriation for antitoxin treatment because of symptoms of botulism. Because there was a shortage of antitoxin in the Netherlands, an emergency delivery was requested from the manufacturer in Germany. An outbreak investigation was initiated into all nine cruise members, eight of whom developed symptoms. C. botulinum type B was isolated in stool culture from four of them. No other patients were notified locally. Food histories revealed locally purchased unprocessed black olives, consumed on board of the ship, as most likely source, but no left-overs were available for investigation. C. botulinum type D was detected in locally purchased canned peas, and whilst type D is not known to be a cause of human intoxication, its presence in a canned food product indicates an inadequate preserving process. With increasing tourism to areas where food-borne botulism is reported regularly special requests for botulism antitoxin may become necessary. Preparing an inventory of available reserve stock in Europe would appear to be a necessary and valuable undertaking.

Centers for Disease Control and Prevention (CDC). Investigational heptavalent botulinum antitoxin (HBAT) to replace licensed botulinum antitoxin AB and investigational botulinum antitoxin E

CDC announces the availability of a new heptavalent botulinum antitoxin (HBAT, Cangene Corporation) through a CDC-sponsored Food and Drug Administration (FDA) Investigational New Drug (IND) protocol. HBAT replaces a licensed bivalent botulinum antitoxin AB and an investigational monovalent botulinum antitoxin E (BAT-AB and BAT-E, Sanofi Pasteur) with expiration of these products on March 12, 2010. As of March 13, 2010, HBAT became the only botulinum antitoxin available in the United States for naturally occurring noninfant botulism.

[Two horses with neurological symptoms: could this be equine botulism?]

Symptoms, diagnosis and therapy of equine botulism are discussed by the presentation of two detailed reports of horses with neurological symptoms and the results of laboratory investigations over the period 2003-2008 in the Netherlands. In addition a brief summary of the available literature is presented. Prevailing symptoms of botulism in horses include paralysis of the tongue, salvation, dysphagia and paresis and paralysis of the skeletal muscles, as well as signs of colic. Symptoms and prognosis vary with the amount of botulinum neurotoxin (BoNT) involved. For early clinical diagnosis of botulism thorough investigation of the facial nerves is important, for instance by the use of the 'Tongue Stress Test'. Laboratory results often remain negative, probably due to the sampling time, the high sensitivity of horses for botulinum neurotoxin or treatment with antitoxins. Most clinical cases in horses are caused by botulinum neurotoxin B (BoNT/B). For therapy to be successful antiserum needs to be administered in the earliest possible stage of the disease and this should be supported by symptomatic therapy. Botulism is a feed-related intoxication caused by either carcasses in the roughage or BoNT/B production after poor conservation of grass silage. This is the main source of botulism in horses due to the popularity of individually packed grass silage as feed for horses. As long as no vaccine is available in the Netherlands quality control of silage and haylage is strictly recommended in order to reduce the risk of botulism in horses.

[Botulism--actual epidemiologic and clinical problem]

Botulism incidence in Poland is the highest in whole European Union. Polish emigrants suffer from botulism as well. This phenomenon is supposed to be caused by Polish custom of preparing home-made food. The most frequent clinical forms of botulism are: foodborne botulism, wound botulism and infant botulism. The diagnosis is mostly made on case history, physical examination and it is confirmed by toxin detection in food remains, vomits and stool. In treatment of adult's botulism antitoxin derived from hyperimmunizated horses, but in infant botulism human immunoglobulin should be used.

[Infant botulism: case report and review]

Botulism is a rare disease in Chile and of the known clinical presentation, infant botulism is the most common. We report the case of a previously healthy seven month old male infant with a two weeks history of rinorrea, cough, fatigue, constipation and progressive weakness after the consumption of honey. Stool cultures were positive for Clostridium botulinum group 1 type A and electromyography was compatible with the diagnosis. The patient evolved with arterial hypertension, interpreted as secondary to autonomic dysfunction, which responded to calcium channel blockers. Muscle tone improved progressively during the following four weeks. Infant botulism is a potentially fatal disease; diagnosis can be difficult given the broad clinical manifestations. Prevention should focus on education of parents of infants as well as medical personnel.

Denmark: botulism in an infant or infant botulism?

A 4.5 months old, previously healthy Danish girl was admitted to a paediatric department after six days of passive behaviour and weak suck. Over the next days she became increasingly weak, developed bilateral ptosis, the muscle stretch reflexes were lost, and mydriasis with slow pupillary responses was noted. Botulism was suspected and confirmed by testing of patient serum in a bioassay. The condition of the patient improved following administration of botulism antiserum. The clinical picture was suggestive of intestinal (infant) botulism. However, botulism acquired from consumption of food with preformed neurotoxin could not be excluded.

Antimicrobial resistance and the management of anaerobic infections

Management of anaerobic infections encompasses surgical procedures, antibacterial therapy and adjuncts. At present, metronidazole, penems, beta-lactam/beta-lactamase inhibitor combinations and chloramphenicol have the highest activity against obligate anaerobes. Tigecycline is a promising new agent. Other antibacterials (e.g., nitazoxanide, moxifloxacin, garenoxacin and ramoplanin) and nonantibiotic agents show potential but need further investigation. The patient's characteristics, mixed anaerobic/aerobic infections, infection sites, bacterial resistance patterns, bactericidal activity of agents and their pharmacokinetics, toxicity and influence on the normal flora should be considered. Susceptibility patterns of anaerobes have become less predictable owing to increasing antibacterial resistance. Emergence of highly virulent or multidrug-resistant strains is challenging the current therapy. To counteract these trends, regular resistance surveillance in anaerobes, rational antibiotic use and evaluation of new treatment alternatives are important.