A single-case foodborne botulism outbreak caused by Clostridium botulinum type A1(B5) in diced garlic in Newfoundland and Labrador, 2024

Foodborne botulism is a severe neuroparalytic disease caused by ingestion of foods containing botulinum neurotoxins, produced by Clostridium botulinum. In 2024, a 74-year-old woman from Newfoundland and Labrador with complete bilateral flaccid paralysis and respiratory distress was hospitalized and required intubation. From the broader differential diagnosis list, botulism was favoured prior to laboratory confirmation. Serum and feces samples initially tested negative for botulinum neurotoxins by mouse bioassay, yet viable C. botulinum type A was recovered from the feces. Food history investigation included some diced garlic in a repurposed coffee container that tested negative for botulinum neurotoxins by mouse bioassay, but viable C. botulinum type A was recovered from the sample. Both the fecal and garlic enrichment cultures were positive for bont/A and bont/B genes by real-time PCR. Whole genome sequencing revealed that both fecal and garlic isolates were highly similar with conserved gene synteny, including an intact bont/A1 gene and a disrupted (silent) bont/B5 gene encoded on the chromosome. This single-case foodborne botulism outbreak from Newfoundland and Labrador in 2024 was caused by C. botulinum type A1(B5) in diced garlic.