Foodborne botulism in Canada, 1985-2005

Navigating the Complexities Involving the Identification of Botulinum Neurotoxins (BoNTs) and the Taxonomy of BoNT-Producing Clostridia

Botulinum neurotoxins are a varied group of protein toxins that share similar structures and modes of activity. They include at least seven serotypes and over forty subtypes that are produced by seven different clostridial species. These bacterial species are not limited strictly to BoNT-producers as neuro-toxigenic and non-neuro-toxigenic members have been identified within each species. The nomenclature surrounding these toxins and associated bacteria has been evolving as new isolations and discoveries have arisen, resulting in challenges in diagnostic reporting, epidemiology and food safety studies, and in the application of therapeutic products. An understanding of the intricacies regarding the nomenclature of BoNTs and BoNT-producing clostridia is crucial for communication that allows for accurate reporting of information that is pertinent to each situation.

Foodborne Botulism, Canada, 2006-20211

During 2006-2021, Canada had 55 laboratory-confirmed outbreaks of foodborne botulism, involving 67 cases. The mean annual incidence was 0.01 case/100,000 population. Foodborne botulism in Indigenous communities accounted for 46% of all cases, which is down from 85% of all cases during 1990-2005. Among all cases, 52% were caused by botulinum neurotoxin type E, but types A (24%), B (16%), F (3%), and AB (1%) also occurred; 3% were caused by undetermined serotypes. Four outbreaks resulted from commercial products, including a 2006 international outbreak caused by carrot juice. Hospital data indicated that 78% of patients were transferred to special care units and 70% required mechanical ventilation; 7 deaths were reported. Botulinum neurotoxin type A was associated with much longer hospital stays and more time spent in special care than types B or E. Foodborne botulism often is misdiagnosed. Increased clinician awareness can improve diagnosis, which can aid epidemiologic investigations and patient treatment.

Epidemiological Analysis of Foodborne Botulism Outbreaks - China, 2004-2020

Introduction

Foodborne botulism is a rare, potentially fatal illness resulting from the ingestion of foods contaminated with preformed botulinum neurotoxin types A, B, E, or F, produced by Clostridium botulinum. The descriptive epidemiology of foodborne botulism outbreaks in China during 2004-2020 was performed to inform public health response strategies.

Methods

Data from 22 of 31 provincial-level administrative divisions (PLADs) of the National Foodborne Disease Outbreaks Surveillance System during 2004-2020 and Embase, China National Knowledge Infrastructure (CNKI), Wanfang Data, and Chinese Science and Technique Journals (CQVIP) from January 2004 to December 2020 to identify indexed publications in the Chinese literature using the following search terms "botulism," or "botulinum toxin," or "Clostridium botulinum." The number and proportion of outbreaks, illnesses, and deaths by PLAD, food types, and contributing factors were calculated.

Results

During 2004-2020, a total of 80 foodborne botulism outbreaks occurred in China, involving 386 illnesses and 55 deaths; most outbreaks were reported between June and August, with a sharp peak in January; 22 out of 31 PLADs reported foodborne botulism outbreaks, Xinjiang reported the largest number of outbreaks (20), followed by Qinghai (13); the most commonly implicated foods were home-prepared traditional processed stinky tofu and dried beef, accounting for 51.25% events. Improper processing and improper storage in contributing factors accounted for 77.50% outbreaks. Initial misdiagnosis occurred in 27.50% of cases.

Conclusions

Outbreaks of foodborne botulism had a high case-fatality rate. Targeted food safety and popularization education to farmers and herdsmen in Xinjiang and Qinghai related to botulism prevention should be carried out, and timely outbreak investigation and hospital surge capacity should be improved.

Draft Genome Sequences of Two Clostridium botulinum Group II Strains Carrying Phage-Like Plasmids

Clostridium botulinum is responsible for botulism, a potentially lethal foodborne intoxication. Here, we report the draft genome sequences of C. botulinum group II strains 202F (serotype F) and Hazen (serotype E). The genomes share many similarities, including multiple mobile genetic elements.

Implications of Zoonoses From Hunting and Use of Wildlife in North American Arctic and Boreal Biomes: Pandemic Potential, Monitoring, and Mitigation

The COVID-19 pandemic has re-focused attention on mechanisms that lead to zoonotic disease spillover and spread. Commercial wildlife trade, and associated markets, are recognized mechanisms for zoonotic disease emergence, resulting in a growing global conversation around reducing human disease risks from spillover associated with hunting, trade, and consumption of wild animals. These discussions are especially relevant to people who rely on harvesting wildlife to meet nutritional, and cultural needs, including those in Arctic and boreal regions. Global policies around wildlife use and trade can impact food sovereignty and security, especially of Indigenous Peoples. We reviewed known zoonotic pathogens and current risks of transmission from wildlife (including fish) to humans in North American Arctic and boreal biomes, and evaluated the epidemic and pandemic potential of these zoonoses. We discuss future concerns, and consider monitoring and mitigation measures in these changing socio-ecological systems. While multiple zoonotic pathogens circulate in these systems, risks to humans are mostly limited to individual illness or local community outbreaks. These regions are relatively remote, subject to very cold temperatures, have relatively low wildlife, domestic animal, and pathogen diversity, and in many cases low density, including of humans. Hence, favorable conditions for emergence of novel diseases or major amplification of a spillover event are currently not present. The greatest risk to northern communities from pathogens of pandemic potential is via introduction with humans visiting from other areas. However, Arctic and boreal ecosystems are undergoing rapid changes through climate warming, habitat encroachment, and development; all of which can change host and pathogen relationships, thereby affecting the probability of the emergence of new (and re-emergence of old) zoonoses. Indigenous leadership and engagement in disease monitoring, prevention and response, is vital from the outset, and would increase the success of such efforts, as well as ensure the protection of Indigenous rights as outlined in the United Nations Declaration on the Rights of Indigenous Peoples. Partnering with northern communities and including Indigenous Knowledge Systems would improve the timeliness, and likelihood, of detecting emerging zoonotic risks, and contextualize risk assessments to the unique human-wildlife relationships present in northern biomes.

Toxemia in Human Naturally Acquired Botulism

Human botulism is a severe disease characterized by flaccid paralysis and inhibition of certain gland secretions, notably salivary secretions, caused by inhibition of neurotransmitter release. Naturally acquired botulism occurs in three main forms: food-borne botulism by ingestion of preformed botulinum neurotoxin (BoNT) in food, botulism by intestinal colonization (infant botulism and intestinal toxemia botulism in infants above one year and adults), and wound botulism. A rapid laboratory confirmation of botulism is required for the appropriate management of patients. Detection of BoNT in the patient's sera is the most direct way to address the diagnosis of botulism. Based on previous published reports, botulinum toxemia was identified in about 70% of food-borne and wound botulism cases, and only in about 28% of infant botulism cases, in which the diagnosis is mainly confirmed from stool sample investigation. The presence of BoNT in serum depends on the BoNT amount ingested with contaminated food or produced locally in the intestine or wound, and the timeframe between serum sampling and disease onset. BoNT levels in patient's sera are most frequently low, requiring a highly sensitive method of detection. Mouse bioassay is still the most used method of botulism identification from serum samples. However, in vitro methods based on BoNT endopeptidase activity with detection by mass spectrometry or immunoassay have been developed and depending on BoNT type, are more sensitive than the mouse bioassay. These new assays show high specificity for individual BoNT types and allow more accurate differentiation between positive toxin sera from botulism and autoimmune neuropathy patients.

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.

Towards a better understanding of the benefits and risks of country food consumption using the case of walruses in Nunavik (Northern Quebec, Canada)

Food insecurity affects Inuit communities. One solution is to consume locally harvested foods, named country foods. However, some country foods are not eaten as often as before, and pressures including contaminants and environmental changes threaten the health of Arctic fauna, thus its suitability for local consumption. By combining Inuit Knowledge with laboratory data, our study assessed the benefits and risks of walrus consumption by Inuit in Nunavik, Québec, Canada. It aimed to increase understanding of: 1) the hunt of healthy Atlantic walruses (Odobenus rosmarus rosmarus); 2) the safe preparation of walruses; 3) the nutritional benefits and risks of consuming walruses. To do so, we interviewed 34 hunters and Elders from Nunavik. Levels of mercury, omega-3 polyunsaturated fatty acids and selenium were evaluated from locally harvested walruses. Through the Nunavik Trichinellosis Prevention Program, a total of 755 Atlantic walrus samples, collected between 1994 and 2013, were tested for Trichinella nativa. Information on botulism was reviewed. While interviews informed on how to select healthy walruses and prepare them for consumption, laboratory analyses revealed that walruses had elevated levels of omega-3 fatty acids and selenium but low levels of mercury compared to some other wildlife. Only 3% of the 755 walruses were infected with T. nativa. Most walruses' infections were found within individuals from the South East Hudson Bay stock, where Inuit have thus decided to stop hunting since mid-2000s. Finally, although the number of outbreaks of trichinellosis related to the consumption of walruses has significantly reduced in Nunavik, botulism could continue to be an issue when igunaq (i.e. aged walrus) is not properly prepared. With the support of the Nunavik Trichinellosis Prevention Program and transmission of Inuit knowledge on igunaq preparation, the consumption of Atlantic walruses has the potential to help address issues related to food insecurity in Nunavik in the future.

Assessment of the risk of botulism from chilled, vacuum/modified atmosphere packed fresh beef, lamb and pork held at 3 °C-8 °C

The safety of current UK industry practice (including shelf-life) for chilled, vacuum/modified atmosphere-packed fresh red meat (beef, lamb and pork) held at 3°C-8°C has been evaluated with respect to non-proteolytic Clostridium botulinum. UK industry typically applies a retail pack shelf-life at 3°C-8°C to 13 days for fresh red meat, with a maximum of 23 days for beef, 27 days for lamb, and 18 days for pork. An exposure assessment established that current commercial practice for fresh red meat provided strong protection with more than 10¹⁰ person servings marketed in the UK without association with foodborne botulism. A challenge test demonstrated that spores of non-proteolytic C. botulinum inoculated on chilled vacuum-packed fresh red meat did not lead to detectable neurotoxin at day 50 for beef, day 35 for lamb, or day 25 for pork (i.e. <40 pg type B toxin and type E toxin g^-1 of meat). The products were visually spoiled many days before these end points. The exposure assessment and challenge test demonstrated the safety of current UK industry practices for the shelf-life of fresh, vacuum-packed beef, lamb and pork held at 3°C-8°C with respect to C. botulinum, and that botulinum neurotoxin was not detected within their organoleptic shelf-life.

The use of the so-called 'tubs' for transporting and storing fresh fishery products

On-land transport/storage of fresh fishery products (FFP) for up to 3 days in 'tubs' of three-layered poly-ethylene filled with freshwater and ice was compared to the currently authorised practice (fish boxes of high-density poly-ethylene filled with ice). The impact on the survival and growth of biological hazards in fish and the histamine production in fish species associated with a high amount of histidine was assessed. In different modelling scenarios, the FFP are stored on-board in freshwater or seawater/ice (in tubs) and once on-land they are 'handled' (i.e. sorted or gutted and/or filleted) and transferred to either tubs or boxes. The temperature of the FFP was assumed to be the most influential factor affecting relevant hazards. Under reasonably foreseeable 'abusive' scenarios and using a conservative modelling approach, the growth of the relevant hazards (i.e. Listeria monocytogenes, Aeromonas spp. and non-proteolytic Clostridium botulinum), is expected to be < 0.2 log10 units higher in tubs than in boxes after 3 days when the initial temperature of the fish is 0°C ('keeping' process). Starting at 7°C ('cooling-keeping' process), the expected difference in the growth potential is higher (< 1 log10 for A. hydrophila and < 0.5 log10 for the other two hazards) due to the poorer cooling capacity of water and ice (tub) compared with ice (box). The survival of relevant hazards is not or is negligibly impacted. Histamine formation due to growth of Morganella psychrotolerans under the 'keeping' or 'cooling-keeping' process can be up to 0.4 ppm and 1.5 ppm higher, respectively, in tubs as compared to boxes after 3 days, without reaching the legal limit of 100 ppm. The water uptake associated with the storage of the FFP in tubs (which may be up to 6%) does not make a relevant contribution to the differences in microbial growth potential compared to boxes.

Adult Intestinal Toxemia Botulism

Intoxication with botulinum neurotoxin can occur through various routes. Foodborne botulism results after consumption of food in which botulinum neurotoxin-producing clostridia (i.e., Clostridium botulinum or strains of Clostridiumbutyricum type E or Clostridiumbaratii type F) have replicated and produced botulinum neurotoxin. Infection of a wound with C. botulinum and in situ production of botulinum neurotoxin leads to wound botulism. Colonization of the intestine by neurotoxigenic clostridia, with consequent production of botulinum toxin in the intestine, leads to intestinal toxemia botulism. When this occurs in an infant, it is referred to as infant botulism, whereas in adults or children over 1 year of age, it is intestinal colonization botulism. Predisposing factors for intestinal colonization in children or adults include previous bowel or gastric surgery, anatomical bowel abnormalities, Crohn's disease, inflammatory bowel disease, antimicrobial therapy, or foodborne botulism. Intestinal colonization botulism is confirmed by detection of botulinum toxin in serum and/or stool, or isolation of neurotoxigenic clostridia from the stool, without finding a toxic food. Shedding of neurotoxigenic clostridia in the stool may occur for a period of several weeks. Adult intestinal botulism occurs as isolated cases, and may go undiagnosed, contributing to the low reported incidence of this rare disease.

Recalls of Foods due to Microbial Contamination Classified by the Canadian Food Inspection Agency, 2000 to 2017

Recall of microbial-contaminated food products is an important intervention in preventing the transmission of foodborne illness. Here, we summarize the number and nature of foods recalled as a result of microbial contamination, classified by the Canadian Food Inspection Agency, for the period 1 January 2000 through 31 December 2017. A total of 10,432 food products were recalled from 2,094 recall events in Canada because of microbial contamination during this period. The meat, meat products and poultry category, followed by fishery and seafood products and nuts and edible seeds, contained the food products most commonly associated with microbial contamination. Most microbial-contaminated food products reported were recalled because of the presence bacterial pathogens. Salmonella contamination was responsible for the largest number of recall events, whereas Listeria monocytogenes contamination accounted for the greatest number of food products recalled because of microbial contamination. L. monocytogenes contamination was also most commonly associated with major food recall events, although records may be inflated because of an invested effort to prevent future L. monocytogenes outbreaks following a 2008 deli meat recall. The findings and data we present in this study will support future surveillance and analysis of microbial-contaminated food recalls in Canada.

The Epidemiology of Foodborne Botulism Outbreaks: A Systematic Review

Background

We performed a systematic review of foodborne botulism outbreaks to describe their clinical aspects and descriptive epidemiology in order to inform public health response strategies.

Methods

We searched seven databases for reports of foodborne botulism outbreaks published in English from database inception to May 2015. We summarized descriptive characteristics and analyzed differences in exposure and toxin types by geographic region. We performed logistic regression to assess correlations between exposure source, implicated food, and outbreak size.

Results

There were 197 outbreaks reported between 1920 and 2014. The median number of cases per outbreak was 3 (range 2-97). The majority of reported outbreaks (109; 55%) occurred in the United States. Toxin types A, B, E, and F were identified as the causative agent in 34%, 16%, 17%, and 1% of outbreaks, respectively. The median duration between exposure and symptom onset was approximately 1 day. The mean percentage of cases requiring mechanical ventilation per outbreak was 34%. Seventy percent of all outbreaks and 77% of small outbreaks (≤11 cases) originated from point source exposures, while commercial foods were significantly (odds ratio, 6.9; 95% confidence interval, 2.2-21.1) associated with large outbreaks (≥12 cases).

Conclusions

Toxin type A accounted for half of outbreaks, and these outbreaks had a higher proportion of patient ventilatory failure. Most outbreaks were due to point source exposures, while outbreaks due to commercial food were larger. For effective responses to foodborne botulism outbreaks, these findings demonstrate the need for timely outbreak investigation and hospital surge capacity.

Botulism During Pregnancy and the Postpartum Period: A Systematic Review

Background

Maternal and fetal outcomes associated with botulism and botulinum antitoxin use during pregnancy and the postpartum period have not been systematically reviewed.

Methods

We searched Global Health, Cochrane Library, Cumulative Index to Nursing and Allied Health Literature, Scopus, and Medline databases from inception to May 2015 for studies published on botulism or botulinum antitoxin use during pregnancy and the postpartum period, as well as the Centers for Disease Control and Prevention National Botulism Surveillance database. Our search identified 4517 citations.

Results

Sixteen cases of botulism during pregnancy (11 in the third trimester) and 1 case during the postpartum period were identified. Ten cases were associated with confirmed or likely foodborne exposure; 2 cases were attributed to wound contamination related to heroin use, and the source of 5 cases was unknown. Eleven women with botulism had progressive neurologic deterioration and respiratory failure, requiring intensive care unit admission. Four women had adverse outcomes, including 2 deaths and 2 women who remained in a persistent vegetative state. No neonatal losses or cases of congenital botulism were reported. Among the 12 cases that reported neonatal data, 6 neonates were born preterm. No adverse maternal or neonatal events were identified as associated with botulinum antitoxin therapy among 11 patients who received it.

Conclusions

Our review of 17 cases of botulism in pregnant/postpartum women found that more than half required ventilator support, 2 women died, and 6 infants were born prematurely. A high level of clinical suspicion is key for early diagnosis and treatment of botulism. Care of pregnant women or new mothers with botulism can include preparation for possible intubation.

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.

Pulsotype Diversity of Clostridium botulinum Strains Containing Serotypes A and/or B Genes

Clostridium botulinum strains are prevalent in the environment and produce a potent neurotoxin that causes botulism, a rare but serious paralytic disease. In 2010, a national PulseNet database was established to curate C. botulinum pulsotypes and facilitate epidemiological investigations, particularly for serotypes A and B strains frequently associated with botulism cases in the United States. Between 2010 and 2014 we performed pulsed-field gel electrophoresis (PFGE) using a PulseNet protocol, uploaded the resulting PFGE patterns into a national database, and analyzed data according to PulseNet criteria (UPGMA clustering, Dice coefficient, 1.5% position tolerance, and 1.5% optimization). A retrospective data analysis was undertaken on 349 entries comprised of type A and B strains isolated from foodborne and infant cases to determine epidemiological relevance, resolution of the method, and the diversity of the database. Most studies to date on the pulsotype diversity of C. botulinum have encompassed very small sets of isolates; this study, with over 300 isolates, is more comprehensive than any published to date. Epidemiologically linked isolates had indistinguishable patterns, except in four instances and there were no obvious geographic trends noted. Simpson's Index of Diversity (D) has historically been used to demonstrate species diversity and abundance within a group, and is considered a standard descriptor for PFGE databases. Simpson's Index was calculated for each restriction endonuclease (SmaI, XhoI), the pattern combination SmaI-XhoI, as well as for each toxin serotype. The D values indicate that both enzymes provided better resolution for serotype B isolates than serotype A. XhoI as the secondary enzyme provided little additional discrimination for C. botulinum. SmaI patterns can be used to exclude unrelated isolates during a foodborne outbreak, but pulsotypes should always be considered concurrently with available epidemiological data.

Foodborne and waterborne illness among Canadian Indigenous populations: A scoping review

Background

Indigenous populations are often at higher risk for foodborne illness than the general Canadian population.

Objective

To investigate the extent of the literature on the link between food safety and the occurrence of foodborne and waterborne illness in Canadian Indigenous populations.

Methods

A scoping review was conducted using search strings in five databases and grey literature to identify all papers that studied a Canadian Indigenous population and referred to any potential associations between food safety (including consumption and preparation of traditional foods and retail foods) or water safety practices and food or waterborne illness. Two authors screened papers based on inclusion and exclusion criteria. Included documents were analyzed for emergent themes.

Results

From 1,718 unique records identified, 21 documents were selected. Foodborne illness was most common in children up to 14 years old. Walrus, seal, caribou and whale were the most common traditional foods tied to foodborne illness and were primarily associated with botulism and trichinosis. Aside from consuming the food raw, fermentation was the most common traditional preparation method linked to foodborne illness. There was concern about the safety of retail food but no clear link was identified with foodborne illness. Lastly, although there was concern about tap water, the use of alternate water sources, such as untreated brook water, and hygiene and cleaning practices in communities with boil water advisories were the most common risk behaviours associated with waterborne illness.

Conclusion

Consumption of certain game meats, as well as the use of traditional fermentation practices may lead to an increased risk of foodborne illness among Indigenous populations. Concern about tap water may lead to use of unsafe alternate water sources. Further research is needed to examine potential culturally appropriate food and water safety opportunities.

Tracking sources of Clostridium botulinum type E contamination in seal meat

Botulism in Nunavik, Quebec is associated with the consumption of aged marine mammal meat and fat. The objective was to identify meat handling practices presenting a risk of contamination of seal meat with C. botulinum. Potential sources of contamination were assessed through interviews with igunaq producers from five communities of Nunavik. These sources were verified by detection and isolation of C. botulinum from igunaq prepared in the field from seal carcasses. Interviews indicated practices presenting a risk for contamination included: placing meat or fat on coastal rocks, using seawater for rinsing, and ageing meat in inverted seal skin pouches. Although the presence of C. botulinum type E spores was detected in only two of 32 (6.3%) meat or fat samples collected during the butchering process, two of four igunaq preparations from these samples contained type E botulinum toxin. Analysis of C. botulinum type E isolates recovered from these preparations indicated that shoreline soil may be a source of contamination. Seal meat and fat may be contaminated with C. botulinum type E during the butchering process. Measures can be adopted to reduce the risks of contamination in the field and possibly decrease the incidence of type E botulism in Nunavik.

Evolution of Chromosomal Clostridium botulinum Type E Neurotoxin Gene Clusters: Evidence Provided by Their Rare Plasmid-Borne Counterparts

Analysis of more than 150 Clostridium botulinum Group II type E genomes identified a small fraction (6%) where neurotoxin-encoding genes were located on plasmids. Seven closely related (134–144 kb) neurotoxigenic plasmids of subtypes E1, E3, and E10 were characterized; all carried genes associated with plasmid mobility via conjugation. Each plasmid contained the same 24-kb neurotoxin cluster cassette (six neurotoxin cluster and six flanking genes) that had split a helicase gene, rather than the more common chromosomal rarA. The neurotoxin cluster cassettes had evolved as separate genetic units which had either exited their chromosomal rarA locus in a series of parallel events, inserting into the plasmid-borne helicase gene, or vice versa. A single intact version of the helicase gene was discovered on a nonneurotoxigenic form of this plasmid. The observed low frequency for the plasmid location may reflect one or more of the following: 1) Less efficient recombination mechanism for the helicase gene target, 2) lack of suitable target plasmids, and 3) loss of neurotoxigenic plasmids. Type E1 and E10 plasmids possessed a Clustered Regularly Interspaced Short Palindromic Repeats locus with spacers that recognized C. botulinum Group II plasmids, but not C. botulinum Group I plasmids, demonstrating their long-term separation. Clostridium botulinum Group II type E strains also carry nonneurotoxigenic plasmids closely related to C. botulinum Group II types B and F plasmids. Here, the absence of neurotoxin cassettes may be because recombination requires both a specific mechanism and specific target sequence, which are rarely found together.

Pregnancy outcomes following exposure to onabotulinumtoxinA

PURPOSE

To evaluate pregnancy outcomes following onabotulinumtoxinA (US Food and Drug Administration pregnancy category C product) exposure using the Allergan safety database.

METHODS

The Allergan Global Safety Database contains reports of onabotulinumtoxinA administration before/during pregnancy, including both prospective (reported before outcome) and retrospective (outcome already known) cases. The database was searched from 1/1/90 to 12/31/13 for eligible cases where treatment occurred during pregnancy or ≤3 months before conception. To minimize reporting bias, prevalence rates were focused on prospective cases.

RESULTS

Of 574 pregnancies with maternal onabotulinumtoxinA exposure, 232 were eligible with known outcomes. Patients received onabotulinumtoxinA most frequently for cosmetic indications (50.5%), movement disorders (16.8%), and pain disorders (14.2%). Of the 137 with dose information, 40.1% received <50U, 14.6% 50U to <100U, 27.7% 100U to <200U, and 17.5% ≥200U. Among 146 cases with known maternal age, 47.9% were ≥35 years. Most (96.0%) fetal exposures occurred during/before the first trimester. Of the 137 prospective cases (139 fetuses), 110 (79.1%) were live births; 29 (20.9%; 95% CI, 14.0-30.0%) ended in fetal loss (21 spontaneous, 8 induced abortions). Among live births, 106 (96.4%) were normal, with four abnormal birth outcomes (1 major fetal defect, 2 minor fetal malformations, 1 birth complication), giving a 2.7% (3/110; 95% CI, 0.6-8.0%) prevalence rate for overall fetal defects.

CONCLUSIONS

A 24-year retrospective review of the Allergan safety database shows that the prevalence of fetal defects in onabotulinumtoxinA-exposed mothers before/during pregnancy (2.7%) is comparable with background rates in the general population. Pregnancy outcome monitoring in onabotulinumtoxinA-exposed women continues.

Retrospective survey to evaluate the safety and efficacy of Japanese botulinum antitoxin therapy in Japan

Japanese botulinum antitoxins have been used for more than 50 years; however, their safety and therapeutic efficacy are not clear. In order to analyze the available data on botulinum antitoxin therapy in Japan, we surveyed published reports about botulism cases in which botulinum antitoxins were used, and retrospectively analyzed the safety and efficacy of the therapy. A total of 134 patients administered botulinum antitoxins were identified from published reports. Two cases of side effects (1.5%) were detected after antitoxin administration, both not fatal. The fatality rate was 9.4%, and more than 70% of the patients showed improvement in their symptoms and better clinical conditions than those not treated with antitoxins. These data suggest that the therapy with Japanese antitoxins is safe and highly effective.

Association of Anti-GT1a Antibodies with an Outbreak of Guillain-Barré Syndrome and Analysis of Ganglioside Mimicry in an Associated Campylobacter jejuni Strain

An outbreak of Guillain-Barré syndrome (GBS), subsequent to Campylobacter jejuni enteritis, occurred in China in 2007. Serum anti-ganglioside antibodies were measured in GBS patients and controls. Genome sequencing was used to determine the phylogenetic relationship among three C. jejuni strains from a patient with GBS (ICDCCJ07001), a patient with gastroenteritis (ICDCCJ07002) and a healthy carrier (ICDCCJ07004), which were all associated with the outbreak. The ganglioside-like structures of the lipo-oligosaccharides of these strains were determined by mass spectrometry. Seventeen (53%) of the GBS patients had anti-GT1a IgG antibodies. GT1a mimicry was found in the lipo-oligosaccharides of strain ICDCCJ07002 and ICDCCJ07004; but a combination of GM3/GD3 mimics was observed in ICDCCJ07001, although this patient had anti-GT1a IgG antibodies. A single-base deletion in a glycosyltransferase gene caused the absence of GT1a mimicry in ICDCCJ07001. The phylogenetic tree showed that ICDCCJ07002 and ICDCCJ07004 were genetically closer to each other than to ICDCCJ07001. C. jejuni, bearing a GT1a-like lipo-oligosaccharide, might have caused the GBS outbreak and the loss of GT1a mimicry may have helped ICDCCJ07001 to survive in the host.

Clostridium botulinum Group II Isolate Phylogenomic Profiling Using Whole-Genome Sequence Data

Clostridium botulinum group II isolates (n = 163) from different geographic regions, outbreaks, and neurotoxin types and subtypes were characterized in silico using whole-genome sequence data. Two clusters representing a variety of botulinum neurotoxin (BoNT) types and subtypes were identified by multilocus sequence typing (MLST) and core single nucleotide polymorphism (SNP) analysis. While one cluster included BoNT/B4/F6/E9 and nontoxigenic members, the other comprised a wide variety of different BoNT/E subtype isolates and a nontoxigenic strain. In silico MLST and core SNP methods were consistent in terms of clade-level isolate classification; however, core SNP analysis showed higher resolution capability. Furthermore, core SNP analysis correctly distinguished isolates by outbreak and location. This study illustrated the utility of next-generation sequence-based typing approaches for isolate characterization and source attribution and identified discrete SNP loci and MLST alleles for isolate comparison.

Fatal outbreak of botulism in Greenland

Botulism commonly occurs when the anaerobic, gram-positive bacterium Clostridium botulinum, under suitable conditions, produces botulinum neurotoxins. Named A-F, these toxins are the immediate causative agent of the clinical symptoms of symmetrical, descending neurological deficits, including respiratory muscle paralysis. We present five cases of foodborne botulism occurring in Greenland, two with fatal outcome, caused by ingestion of tradionally preserved eider fowl. In the cases of the survivors, antitoxin and supportive care, including mechanical ventilation, were administered. In these cases recovery was complete. Microbiological assays, including toxin neutralization bioassay, demonstrated the presence of neurotoxin E in two survivors. The third survivor was shown by PCR to have the BoNT type E gene in faeces. This is the first report of cases of fatal botulism in Greenland. It underscores the importance of prompt coordinated case management effort in a geographically isolated area such as Greenland.

Genomic sequences of six botulinum neurotoxin-producing strains representing three clostridial species illustrate the mobility and diversity of botulinum neurotoxin genes

The whole genomes for six botulinum neurotoxin-producing clostridial strains were sequenced to provide references for under-represented toxin types, bivalent strains or unusual toxin complexes associated with a bont gene. The strains include three Clostridium botulinum Group I strains (CDC 297, CDC 1436, and Prevot 594), a Group II C. botulinum strain (Eklund 202F), a Group IV Clostridium argentinense strain (CDC 2741), and a Group V Clostridium baratii strain (Sullivan). Comparisons of the Group I genomic sequences revealed close relationships and conservation of toxin gene locations with previously published Group I C. botulinum genomes. The bont/F6 gene of strain Eklund 202F was determined to be a chimeric toxin gene composed of bont/F1 and bont/F2. The serotype G strain CDC 2741 remained unfinished in 20 contigs with the bont/G located within a 1.15Mb contig, indicating a possible chromosomal location for this toxin gene. Within the genome of C. baratii Sullivan strain, direct repeats of IS1182 insertion sequence (IS) elements were identified flanking the bont/F7 toxin complex that may be the mechanism of bont insertion into C. baratii. Highlights of the six strains are described and release of their genomic sequences will allow further study of unusual neurotoxin-producing clostridial strains.

Mechanisms of food processing and storage-related stress tolerance in Clostridium botulinum

Vegetative cultures of Clostridium botulinum produce the extremely potent botulinum neurotoxin, and may jeopardize the safety of foods unless sufficient measures to prevent growth are applied. Minimal food processing relies on combinations of mild treatments, primarily to avoid deterioration of the sensory qualities of the food. Tolerance of C. botulinum to minimal food processing is well characterized. However, data on effects of successive treatments on robustness towards further processing is lacking. Developments in genetic manipulation tools and the availability of annotated genomes have allowed identification of genetic mechanisms involved in stress tolerance of C. botulinum. Most studies focused on low temperature, and the importance of various regulatory mechanisms in cold tolerance of C. botulinum has been demonstrated. Furthermore, novel roles in cold tolerance were shown for metabolic pathways under the control of these regulators. A role for secondary oxidative stress in tolerance to extreme temperatures has been proposed. Additionally, genetic mechanisms related to tolerance to heat, low pH, and high salinity have been characterized. Data on genetic stress-related mechanisms of psychrotrophic Group II C. botulinum strains are scarce; these mechanisms are of interest for food safety research and should thus be investigated. This minireview encompasses the importance of C. botulinum as a food safety hazard and its central physiological characteristics related to food-processing and storage-related stress. Special attention is given to recent findings considering genetic mechanisms C. botulinum utilizes in detecting and countering these adverse conditions.

Outbreak of type E foodborne botulism linked to traditionally prepared salted fish in Ontario, Canada

On April 17, 2012, two adult females presented to the hospital with symptoms of botulism. Patient A displayed shortness of breath, increasing lethargy, ptosis, and fixed and dilated pupils, and was intubated after admission. Patient B presented with shortness of breath, vomiting, and stridor. Both patients consumed a meal consisting of a traditionally prepared salted fish, fesikh, on the evening of April 16 during a gathering to celebrate Sham el-Nessim, an Egyptian holiday marking the beginning of spring. Foodborne botulism was suspected based on symptoms and consumption of potentially hazardous food. Antitoxin was administered to both patients on April 18. Another attendee of the Sham el-Nessim gathering (patient C), who also consumed the implicated food, developed symptoms consistent with botulism on April 18. Clinical specimens from all three symptomatic attendees tested positive for either Clostridium botulinum or type E botulinum neurotoxin. Fesikh remaining from the shared meal contained both type E botulinum neurotoxin and C. botulinum type E organisms. Unsold fesikh shad and fesikh sardines tested positive for C. botulinum type E, while unsold fesikh mullet pieces in oil tested positive for both C. botulinum type E and type E botulinum neurotoxin. After consultation with public health investigators, all fesikh products were voluntarily withheld from sale by the manufacturer prior to laboratory confirmation of contamination. Additional illnesses were likely prevented by these precautionary holds, which underscores the importance of timely public health action based on epidemiological evidence available in advance of laboratory results. This is the first documented outbreak of foodborne botulism associated with fesikh to occur in Canada.

Two novel toxin variants revealed by whole-genome sequencing of 175 Clostridium botulinum type E strains

We sequenced 175 Clostridium botulinum type E strains isolated from food, clinical, and environmental sources from northern Canada and analyzed their botulinum neurotoxin (bont) coding sequences (CDSs). In addition to bont/E1 and bont/E3 variant types, neurotoxin sequence analysis identified two novel BoNT type E variants termed E10 and E11. Strains producing type E10 were found along the eastern coastlines of Hudson Bay and the shores of Ungava Bay, while strains producing type E11 were only found in the Koksoak River region of Nunavik. Strains producing BoNT/E3 were widespread throughout northern Canada, with the exception of the coast of eastern Hudson Bay.

Botulism outbreaks in natural environments - an update

Clostridium botulinum comprises a diverse group of botulinum toxin-producing anaerobic rod-shaped spore-forming bacteria that are ubiquitously distributed in soils and aquatic sediments. Decomposition of plants, algae, and animals creates anaerobic environments that facilitate growth of C. botulinum, which may then enter into food webs leading to intoxication of animals. Via saprophytic utilization of nutrients, the bacteria rapidly sporulate, creating a reservoir of highly robust spores. In the present review, we focus on the occurrence of C. botulinum in non-clinical environments, and examine factors influencing growth and environmental factors associated with botulism outbreaks. We also outline cases involving specific environments and their biota. In wetlands, it has been found that some C. botulinum strains can associate with toxin-unaffected organisms–-including algae, plants, and invertebrates–-in which the bacteria appear to germinate and stay in the vegetative form for longer periods of time. We suggest the need for future investigations to resolve issues related to the environments in which C. botulinum spores may accumulate and germinate, and where the vegetative forms may multiply.

The CLO3403/CLO3404 two-component system of Clostridium botulinum E1 Beluga is important for cold shock response and growth at low temperatures

In order to survive a temperature downshift, bacteria have to sense the changing environment and adjust their metabolism and structure. Two-component signal transduction systems (TCSs) play a central role in sensing and responding to many different environmental stimuli. Although the nonproteolytic (group II) Clostridium botulinum represents a major hazard in chilled foods, the cold adaption mechanisms of group II C. botulinum organisms are not known. Here, we show that the CLO3403/CLO3404 TCS of C. botulinum E1 Beluga is involved in the cold shock response and growth at 12°C. Cold shock induced the expression of the genes encoding the histidine kinase (clo3403) and the response regulator (clo3404) by more than 100-fold after 5 h relative to their expression in a nonshocked culture at the corresponding time point. The involvement of CLO3403/CLO3404 in growth at low temperature was demonstrated by impaired growth of the insertional clo3403 and clo3404 knockout mutants at 12°C compared to the growth of the wild-type culture. Additionally, the inactivation of clo3403 had a negative effect on motility. The growth efficiency at 12°C of the TCS mutants and the motility of the kinase mutants were restored by introducing a plasmid harboring the operon of the CLO3403/CLO3404 TCS. The results suggest that the CLO3403/CLO3404 TCS is important for the cold tolerance of C. botulinum E1 Beluga.