Foodborne Botulism Outbreak Associated with Commercial Nacho Cheese Sauce from a Gas Station Market.
BACKGROUND Botulism is a rare and potentially fatal paralytic disease caused by botulinum neurotoxin (BoNT) In April 2017, four California residents, from two adjacent counties, were hospitalized with suspected foodborne botulism, precipitating an investigation by state and local public health departments in California. METHODS We interviewed suspected botulism patients and their families, inspected the suspect establishment and collected suspect food, and tested patient sera, stool, and gastric aspirates by mouse bioassay for BoNT and/or culture for C. botulinum. We tested suspect food and environmental samples for BoNT and confirmed presumptive positives by direct mouse bioassay and culture, and performed whole genome sequencing on food and clinical isolates. RESULTS In April May 2017, ten patients in the Sacramento area were hospitalized with laboratory confirmed botulism; seven required mechanical ventilation, and one died. Of nine patients with available information, all visited Gas Station X before illness onset where eight reported consuming a commercial nacho cheese sauce. BoNT/A and/or BoNT/A producing Clostridiumbotulinum were detected from each patient and leftover cheese sauce. C. botulinum isolates from four patients were closely related to cheese sauce isolates by whole genome high quality single nucleotide polymorphism analysis. No other botulism cases associated with this nacho cheese sauce were reported elsewhere in the United States. CONCLUSIONS This large foodborne botulism outbreak in California was caused by consumption of commercial nacho cheese sauce dispensed at a gas station market. The epidemiologic and laboratory evidence confirmed the cheese sauce as the source of the outbreak. The cheese sauce was likely locally contaminated although the mechanism is unclear.
Clinical infectious diseases an official publication of the Infectious Diseases Society of America