Tracing and characterization of a family outbreak of subtype B2 botulism linked to homemade pickled eggs in Jinan, China.

Authors

Wen Cui, Chuanmin Ma, Xichen Wang, Jishan Zhang, Lin Zhou, Jian Li, Xia Luo, Hui Sun, Xuefang Xu, Hui Liu

Published in

BMC microbiology. Jul 13, 2026. Epub Jul 13, 2026.

Abstract

Foodborne botulism (FB) results from the ingestion of food contaminated with botulinum neurotoxin. Here, we report a family outbreak of foodborne botulism caused by Clostridium botulinum subtype B2 linked to homemade pickled eggs. On August 13, 2024, the Jinan Center for Disease Control and Prevention and the Shanghe County Center for Disease Control and Prevention collaborated to investigate an outbreak of botulism poisoning related to a family gathering in Shanghe County, Jinan City. A total of 4 people attended the family gathering, three of whom developed clinical symptoms of botulism after consuming pickled eggs. The diagnosis of botulism was suspected through collaborative efforts by the Qilu Medical Prevention and Control Innovation Integration Mechanism and multidisciplinary consultations across multiple hospitals. We detected the bont gene using real-time quantitative PCR (qPCR) in Jinan CDC, determined the toxin serotype by mouse bioassay (MBA) in China CDC and performed whole-genome sequencing of bacterial strains isolated from patient feces, the homemade pickled eggs and soil in both laboratories. It was shown that the toxin type and bont gene were subtype B2, belonging to the ha gene cluster. The Clostridium botulinum strains isolated from two patients were closely related to the strains from the homemade pickled eggs through whole-genome single nucleotide polymorphism analysis. We also found that Clostridium botulinum strains from soil clustered into one branch with those from patients and food, suggesting that the source of Clostridium botulinum contamination may be from soil, although the contamination pathway was not clear. Importantly, our findings provided a basis for clinical antitoxin treatment, in which one patient successfully gave birth after recovery. These results underscore the importance of strengthening public education about the health risks associated with consuming homemade fermented or preserved foods and enhancing the laboratory detection capabilities.

PMID:
42443745
Bibliographic data and abstract were imported from PubMed on 14 Jul 2026.

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