Infant botulism and indications for administration of botulism immune globulin

Production of monoclonal antibodies against botulinum neurotoxin in Nicotiana benthamiana

Botulism is a fatal neurologic disease caused by the botulinum toxin (BoNT) produced by Clostridium botulinum. It is a rare but highly toxic disease with symptoms, such as cramps, nausea, vomiting, diarrhea, dysphagia, respiratory failure, muscle weakness, and even death. Currently, two types of antitoxin are used: equine-derived heptavalent antitoxin and human-derived immunoglobulin (BabyBIG®). However, heptavalent treatment may result in hypersensitivity, whereas BabyBIG®, has a low yield. The present study focused on the development of three anti-BoNT monoclonal antibodies (mAbs), 1B18, C25, and M2, in Nicotiana benthamiana. The plant-expressed mAbs were purified and examined for size, purity and integrity by SDS-PAGE, western blotting and size-exclusion chromatography. Analysis showed that plant-produced anti-BoNT mAbs can fully assemble in plants, can be purified in a single purification step, and mostly remain as monomeric proteins. The efficiency of anti-BoNT mAbs binding to BoNT/A and B was then tested. Plant-produced 1B18 retained its ability to recognize both mBoNT/A1 and ciBoNT/B1. At the same time, the binding specificities of two other mAbs were determined: C25 for mBoNT/A1 and M2 for ciBoNT/B1. In conclusion, our results confirm the use of plants as an alternative platform for the production of anti-BoNT mAbs. This plant-based technology will serve as a versatile system for the development botulism immunotherapeutics.

That head lag is impressive! Infantile botulism in the NICU: a case report

BACKGROUND

Infantile botulism (IB) is a devastating and potentially life-threatening neuromuscular disorder resulting from intestinal colonization by Clostridium botulinum and the resultant toxin production. It can present with constipation, descending paralysis, and, potentially, respiratory failure. Botulism is a diagnosis that is more commonly seen in the pediatric intensive care unit (PICU) or on the general pediatric wards and would not typically be managed in the neonatal intensive care unit (NICU), and therefore requires high clinical suspicion to ensure prompt diagnosis and treatment.

CASE PRESENTATION

We discuss a case where an infant from central Pennsylvania presented to a Level IV NICU rather than to the PICU for an evaluation for sepsis and was uniquely diagnosed with IB. The infant presented with poor oral feeding and reduced oral intake, hypothermia, and lethargy. His symptoms progressed into hypoxia and acute respiratory failure. Interestingly, this infant had no known exposure to honey or any other identifiable sources of botulism contact. The infant's twin brother and the other infants who attended the mother's in-home daycare remained asymptomatic. This infant was initially evaluated and managed for a potential infectious etiology. However, a diagnosis of IB was suspected, and was later confirmed through the detection of botulinum toxin in the infant's stools. A high level of suspicion allowed for timely treatment with Botulism Immune Globulin neutralizing antibodies (BabyBIG), even prior to confirmatory testing. We describe the process of obtaining BabyBIG, as well as the natural course of illness after treatment in our patient who ultimately made a complete recovery.

CONCLUSIONS

This case highlights the importance of considering infantile botulism as a diagnostic possibility even in the absence of risk factors, and the need for vigilance in diagnosing and treating this rare but potentially life-threatening condition. With timely recognition, subsequent treatment with BabyBIG, and supportive care, infants with infantile botulism can be expected to recover completely. This information is particularly important for neonatologists providing care for infants outside the neonatal period, especially during times of high patient census and resulting overflow of pediatric admissions in the NICU.

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.