Dual-Toxin ("Bivalent") Infant Botulism in California, 1976-2020: Epidemiologic, Clinical, and Laboratory Aspects.

Objective: To assess the consequences of infant botulism that result from Clostridium botulinum strains that produce 2 botulinum toxin serotypes, termed "bivalent."

Study Design: Epidemiologic investigations used a standard questionnaire. Clostridium botulinum strains were isolated by standard methods.

Closed Genome Sequence of Clostridium botulinum Strain IBCA10-7060 Type Bh.

Clostridium botulinum strain IBCA10-7060 was isolated from a stool specimen from an infant botulism patient and is the only Clostridium botulinum strain known that produces botulinum toxin type H. We present here its 4.09-Mbp closed genome sequence.

The Novel Clostridial Neurotoxin Produced by Strain IBCA10-7060 Is Immunologically Equivalent to BoNT/HA.

Background: Botulinum neurotoxins (BoNTs) comprise seven agreed-on serotypes, A through G. In 2014, a novel chimeric neurotoxin produced by clostridial strain IBCA10-7060 was reported as BoNT/H, with subsequent names of BoNT/FA or BoNT/HA based on sequence homology of the N-terminus to BoNT/F, the C-terminus to BoNT/A and neutralization studies. The purpose of this study was to define the immunologic identity of the novel BoNT.

Antimicrobial Susceptibility of 260 Clostridium botulinum Type A, B, Ba, and Bf Strains and a Neurotoxigenic Clostridium baratii Type F Strain Isolated from California Infant Botulism Patients.

Infant botulism is an infectious intestinal toxemia that results from colonization of the infant large bowel by (or rarely, by neurotoxigenic or ), with subsequent intraintestinal production and absorption of botulinum neurotoxin that then produces flaccid paralysis. The disease is often initially misdiagnosed as suspected sepsis or meningitis, diagnoses that require prompt empirical antimicrobial therapy. Antibiotics may also be needed to treat infectious complications of infant botulism, such as pneumonia or urinary tract infection.

Immunological Characterization and Neutralizing Ability of Monoclonal Antibodies Directed Against Botulinum Neurotoxin Type H.

Background: Only Clostridium botulinum strain IBCA10-7060 produces the recently described novel botulinum neurotoxin type H (BoNT/H). BoNT/H (N-terminal two-thirds most homologous to BoNT/F and C-terminal one-third most homologous to BoNT/A) requires antitoxin to toxin ratios ≥1190:1 for neutralization by existing antitoxins. Hence, more potent and safer antitoxins against BoNT/H are needed.

Notes from the field: infant botulism caused by Clostridium baratii type F - Iowa, 2013.

In June 2013, a male newborn aged 9 days (delivered after a full-term pregnancy) was brought to a hospital emergency department with a 2-day history of constipation, fussiness, and poor feeding. The mother reported her son's symptoms as excessive crying, reluctance to suck, and difficulty in swallowing milk. Within hours of arrival, the infant became less responsive and "floppy," and was intubated for respiratory failure.

Molecular epidemiology of infant botulism in California and elsewhere, 1976-2010.

Background: Infant botulism (IB), first identified in California in 1976, results from Clostridium botulinum spores that germinate, multiply, and produce botulinum neurotoxin (BoNT) in the immature intestine. From 1976 to 2010 we created an archive of 1090 BoNT-producing isolates consisting of 1012 IB patient (10 outpatient, 985 hospitalized, 17 sudden death), 25 food, 18 dust/soils, and 35 other strains.

Methods: The mouse neutralization assay determined isolate toxin type (56% BoNT/A, 32% BoNT/B).

Arrangement of the Clostridium baratii F7 toxin gene cluster with identification of a σ factor that recognizes the botulinum toxin gene cluster promoters.

Botulinum neurotoxin (BoNT) is the most poisonous substances known and its eight toxin types (A to H) are distinguished by the inability of polyclonal antibodies that neutralize one toxin type to neutralize any of the other seven toxin types. Infant botulism, an intestinal toxemia orphan disease, is the most common form of human botulism in the United States. It results from swallowed spores of Clostridium botulinum (or rarely, neurotoxigenic Clostridium butyricum or Clostridium baratii) that germinate and temporarily colonize the lumen of the large intestine, where, as vegetative cells, they produce botulinum toxin.

A novel strain of Clostridium botulinum that produces type B and type H botulinum toxins.

Background: Clostridium botulinum strain IBCA10-7060, isolated from a patient with infant botulism, produced botulinum neurotoxin type B (BoNT/B) and another BoNT that, by use of the standard mouse bioassay, could not be neutralized by any of the Centers for Disease Control and Prevention-provided monovalent polyclonal botulinum antitoxins raised against BoNT types A-G.

Methods And Results:  The combining of antitoxins to neutralize the toxicity of known bivalent C. botulinum strains Ab, Ba, Af, and Bf also failed to neutralize the second BoNT.

Molecular characterization of a novel botulinum neurotoxin type H gene.

We sequenced the 2 botulinum toxin gene clusters of Clostridium botulinum strain IBCA10-7060 type Bh. The sequence of bont/H differed substantially from the sequences of the 7 known bont genes for toxin types A-G. The 5' one-third terminus of bont/H that codes for the botulinum toxin light chain differed markedly from the light chain coding sequences of toxin types A-G.

Clostridium botulinum strain Af84 contains three neurotoxin gene clusters: bont/A2, bont/F4 and bont/F5.

Sanger and shotgun sequencing of Clostridium botulinum strain Af84 type Af and its botulinum neurotoxin gene (bont) clusters identified the presence of three bont gene clusters rather than the expected two. The three toxin gene clusters consisted of bont subtypes A2, F4 and F5. The bont/A2 and bont/F4 gene clusters were located within the chromosome (the latter in a novel location), while the bont/F5 toxin gene cluster was located within a large 246 kb plasmid.

Analysis of Clostridium botulinum serotype E strains by using multilocus sequence typing, amplified fragment length polymorphism, variable-number tandem-repeat analysis, and botulinum neurotoxin gene sequencing.

A total of 41 Clostridium botulinum serotype E strains from different geographic regions, including Canada, Denmark, Finland, France, Greenland, Japan, and the United States, were compared by multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) analysis, variable-number tandem-repeat (VNTR) analysis, and botulinum neurotoxin (bont) E gene sequencing. The strains, representing environmental, food-borne, and infant botulism samples collected from 1932 to 2007, were analyzed to compare serotype E strains from different geographic regions and types of botulism and to determine whether each of the strains contained the transposon-associated recombinase rarA, involved with bont/E insertion. MLST examination using 15 genes clustered the strains into several clades, with most members within a cluster sharing the same BoNT/E subtype (BoNT/E1, E2, E3, or E6).

Presence of soil-dwelling clostridia in commercial powdered infant formulas.

Objective: Because Clostridium botulinum was isolated from powdered infant formula (PIF) fed to an infant in the United Kingdom who subsequently developed infant botulism and from unopened PIF from the same manufacturer, we tested PIF manufactured in the United States for the presence of clostridial spores.

Study Design: Thirty PIF ingested by 19 California infants with botulism within 4 weeks of onset of illness (48% of all patients fed PIF during study) in 2006-2007 were cultured anaerobically to isolate clostridia. All isolated clostridia were identified to the species level and enumerated with standard microbiologic and molecular methods.

Attomolar detection of botulinum toxin type A in complex biological matrices.

Background: A highly sensitive, rapid and cost efficient method that can detect active botulinum neurotoxin (BoNT) in complex biological samples such as foods or serum is desired in order to 1) counter the potential bioterrorist threat 2) enhance food safety 3) enable future pharmacokinetic studies in medical applications that utilize BoNTs.

Methodology/principal Findings: Here we describe a botulinum neurotoxin serotype A assay with a large immuno-sorbent surface area (BoNT/A ALISSA) that captures a low number of toxin molecules and measures their intrinsic metalloprotease activity with a fluorogenic substrate. In direct comparison with the "gold standard" mouse bioassay, the ALISSA is four to five orders of magnitudes more sensitive and considerably faster.

First case of infant botulism caused by Clostridium baratii type F in California.

In late 2003 a severely hypotonic neonate, just 38 h old at onset of illness, was found to have infant botulism caused by neurotoxigenic Clostridium baratii type F. Environmental investigations failed to identify a source of this strain. This is the youngest patient reported to have infant botulism and the fifth instance of infant botulism caused by C.

Dual toxin-producing strain of Clostridium botulinum type Bf isolated from a California patient with infant botulism.

A retrospective study of Clostridium botulinum strains isolated from patients from California with infant botulism identified the fourth known C. botulinum strain that produces both type B and type F botulinum toxins. This unique strain represented 0.