Probiotic Microorganisms Inhibit Epithelial Cell Internalization of Botulinum Neurotoxin Serotype A

Infant Botulism: In Search of Clostridium botulinum Spores

Infant botulism is now the most common form of human botulism in Canada and the United States. Infant botulism is a severe neuroparalytic disease caused by ingestion of the spore-forming neurotoxic clostridia, including Clostridium botulinum that colonize the large intestine and subsequently produce botulinum neurotoxin in situ. It has been over a century since the first surveys documenting the ubiquitous prevalence of C. botulinum in soils around the world. Since then, honey has been identified as the only well-known risk factor for infant botulism despite a multitude of international environmental surveys isolating C. botulinum spores from ground soil, aquatic sediments, and commonly available infant foods. Associations of infant botulism cases with confirmed sources of C. botulinum exposure have primarily implicated outdoor soil and indoor dust, as well as commonly ingested foods including honey, dry cereals, and even powdered infant formula. Yet the origin of infection remains unknown for most infant botulism cases. This review summarizes the various surveys from around the world for C. botulinum in environmental soils and sediments, honey, and other infant foods, as well as laboratory-confirmed associations with documented infant botulism cases. Additional factors are also discussed, including the composition of infant gut microbiota and the practice of breastfeeding. We make several recommendations to better identify sources of exposure to C. botulinum spores that could lead to effective preventive measures and help reduce the incidence of this rare but life-threatening disease.

Case report: Aberrant fecal microbiota composition of an infant diagnosed with prolonged intestinal botulism

BACKGROUND

Intestinal botulism is primarily reported in small babies as a condition known as infant botulism. The condition results from the ingestion of environmental or foodborne spores of botulinum neurotoxin (BoNT) producing Clostridia, usually Clostridium botulinum, and subsequent spore germination into active botulinum neurotoxinogenic cultures in the gut. It is generally considered that small babies are susceptible to C. botulinum colonization because of their immature gut microbiota. Yet, it is poorly understood which host factors contribute to the clinical outcome of intestinal botulism. We previously reported a case of infant botulism where the infant recovered clinically in six weeks but continued to secrete C. botulinum cells and/or BoNT in the feces for seven months.

CASE PRESENTATION

To further understand the microbial ecology behind this exceptionally long-lasting botulinum neurotoxinogenic colonization, we characterized the infant fecal microbiota using 16S rRNA gene amplicon sequencing over the course of disease and recovery. C. botulinum could be detected in the infant fecal samples at low levels through the acute phase of the disease and three months after recovery. Overall, we observed a temporal delay in the maturation of the infant fecal microbiota associated with a persistently high-level bifidobacterial population and a low level of Lachnospiraceae, Bacteroidaceae and Ruminococcaceae compared to healthy infants over time.

CONCLUSION

This study brings novel insights into the infant fecal composition associated with intestinal botulism and provides a basis for a more systematic analysis of the gut microbiota of infants diagnosed with botulism. A better understanding of the gut microbial ecology associated with infant botulism may support the development of prophylactic strategies against this life-threatening disease in small babies.

The Role of Probiotics in Improving Food Safety: Inactivation of Pathogens and Biological Toxins

Currently, many advances have been made in avoiding food contamination by numerous pathogenic and toxigenic microorganisms. Many studies have shown that different probiotics, in addition to having beneficial effects on the host's health, have a very good ability to eliminate and neutralize pathogens and their toxins in foods which leads to enhanced food safety. The present review purposes to comprehensively discuss the role of probiotics in improving food safety by inactivating pathogens (bacterial, fungal, viral, and parasite agents) and neutralizing their toxins in food products. Some recent examples in terms of the anti-microbial activities of probiotics in the body after consuming contaminated food have also been mentioned. This review shows that different probiotics have the potential to inactivate pathogens and neutralize and detoxify various biological agents in foods, as well as in the host body after consumption.

New Strategies for Biocontrol of Bacterial Toxins and Virulence: Focusing on Quorum-Sensing Interference and Biofilm Inhibition

The overuse of antibiotics and the emergence of multiple-antibiotic-resistant pathogens are becoming a serious threat to health security and the economy. Reducing antimicrobial resistance requires replacing antibiotic consumption with more biocontrol strategies to improve the immunity of animals and humans. Probiotics and medicinal plants have been used as alternative treatments or preventative therapies for a variety of diseases caused by bacterial infections. Therefore, we reviewed some of the anti-virulence and bacterial toxin-inhibiting strategies that are currently being developed; this review covers strategies focused on quenching pathogen quorum sensing (QS) systems, the disruption of biofilm formation and bacterial toxin neutralization. It highlights the probable mechanism of action for probiotics and medicinal plants. Although further research is needed before a definitive statement can be made on the efficacy of any of these interventions, the current literature offers new hope and a new tool in the arsenal in the fight against bacterial virulence factors and bacterial toxins.

Potential role of probiotic species in ameliorating oxidative stress, effect on liver profile and hormones in male albino rat model

Probiotics are living micro-organism preparations which can vigorously inhibit the probable pathogens colonization in the gut microbial ecology. Current experiment was designed to investigate the efficacy of imported probiotic species compared with the indigenous probiotics species on the oxidative stress, enzymes, and hormones in animal model. Thirty Albino rats were equally divided into three groups with 10 rats ( n = 10) in each group as Control (C), supplemented with imported probiotic species (IP), and supplemented with indigenous probiotics species (InP) for 21 days under controlled environment. The evaluation of treatments was done by testing the serum oxidative stress markers, liver enzymes (Aspartate transaminase and Alanine aminotransferase), lipid profile, and hormonal dynamics including Lutinizing hormone (LH), follicular stimulating hormone (FSH), and growth hormone (GH) in albino male rats. Results revealed that use of indigenous probiotic species significantly ( p < 0.05) reduces the oxidative stress and improves the antioxidant capacity; liver enzymes, total cholesterol, and LDL-Cholesterol were also reduced significantly ( p < 0.05) in InP as compared to IP group. Moreover, results of hormones including LH, FSH, and GH explored that indigenous probiotics have significant ( p < 0.05) potential to improve these hormones as compared to imported probiotics. Although, it could be concluded that InP have beneficial role in preventing the body from oxidative stress as well as in improving the blood parameters but comprehensive studies are required to investigate the detail gut ecology of the indigenous species which will definitely a strong support in preparing a more suitable local probiotic supplement.

Descriptive Epidemiology of Infant Botulism in California: The First 40 Years

OBJECTIVE

To ascertain the descriptive epidemiology of infant botulism, the flaccid paralysis that results when neurotoxigenic Clostridium species produce botulinum toxin (BoNT) in the infant colon, in its first 40 years following initial recognition in California in 1976.

STUDY DESIGN

Cases were defined by laboratory identification of BoNT and/or neurotoxigenic Clostridium species in patients' feces. Parents were interviewed using a structured questionnaire. Descriptive epidemiologic characteristics were compared between 1976-1996 and 1997-2016.

RESULTS

From 1976-2016, 1345 cases of infant botulism occurred in 45 of 58 California counties (6.5 cases/100 000 live-births/year) caused by BoNT types A, B, Ba, Bf, and F; 88% of cases were ≤6 months of age and 51% were female. Cases were white (84.2%), Asian (8.9%), other races (3.8%), and African American (2.8%); 29.4% of cases were Hispanic. More than 99% of cases were hospitalized. Case occurrence peaked in summer-fall. Of 8 designated geographic regions, the Central Coast counties had 3 times the statewide incidence in both 20-year time periods. Breast-fed patients (83%) were more than twice as old at onset as formula-fed patients (median, 4.4 vs 1.7 months, respectively; P < .001). BoNT/A cases were older at onset than BoNT/B cases (median, 3.8 vs 2.9 months, respectively; P < .001).

CONCLUSIONS

Comprehensive continuous surveillance of infant botulism for 40 years in a large, diversely populated state identified fundamental epidemiologic characteristics of this uncommon illness. Unusual features included greater than 99% case hospitalization, absence of male preponderance, and a distinctive age distribution.

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.

Efficacy and Safety of a Multistrain Probiotic Formulation Depends from Manufacturing

Background

Variability in probiotics manufacturing may affect their properties, with potential implications for their efficacy and safety. This is of particular concern with probiotic products destined for use in patients with serious medical conditions, including human immunodeficiency virus (HIV) infection. The purpose of the study was to carry out a series of experiments comparing the properties of the US-made probiotic formulation originally commercialized under the brand name VSL#3^®, with those of the Italian-made formulation now commercialized under the same name. The US-made formulation has previously shown beneficial effects at the intestinal and neurological levels in HIV-infected subjects as well as in patients with inflammatory bowel diseases and hepatic encephalopathy.

Methods

Eleven subjects receiving combined antiretroviral therapy for HIV-1 were treated for 6 months with the US-made VSL#3 formulation. At baseline and 6 months, T-cells were analyzed for phenotype and activation markers, and fecal samples were analyzed for bifidobacteria, lactobacilli, and their metabolites. The fecal metabolome was assessed using ¹H-NMR spectroscopy. Production of metabolites of interest by bacteria obtained from sachets of the two formulations was compared in vitro and their effects on a rat intestinal epithelial cell line (IEC-6) were assessed. Particular attention was paid to the metabolite 1,3-dihydroxyacetone (DHA).

Results

At 6 months, fecal samples showed a significant increase in the specific bacterial genera contained in the probiotic supplement. Immune activation was reduced as shown by a significant reduction in the percentage of CD4⁺CD38⁺HLA-DR⁺ T-cells at 6 months. Fecal concentrations of DHA decreased significantly. In vitro, significant differences in the production and metabolism of DHA were found between bacteria from the US-made and Italian-made formulations: the US-made formulation was able to metabolize DHA whereas the bacteria in the Italian-made formulation were producing DHA. DHA reduced the viability of Streptococcus thermophilus, reduced IEC-6 cell viability in a dose-dependent manner, and also led to a lower rate of repair to scratched IEC-6 cell monolayer.

Conclusion

Our data, in conjunction with previously published findings, confirm that the new Italian-made formulation of VSL#3^® is different from the previous US-made VSL#3 and therefore its efficacy and safety in HIV-infected subjects is still unproven.