Tracing analysis of an outbreak of food poisoning caused by Shiga toxin-producing Escherichia coli O146∶H10

  Objective  To understand the etiology of a food poisoning outbreak in a school in Guilin, Guangxi.

  Methods  In the epidemiological investigation, stool samples from diarrhea patients, anal swabs from kitchen workers, food, and swabs of kitchen environments were collected. All the samples were screened for pathogens using standard microbiological techniques. The virulence gene profiles were evaluated and the pulsed-field gel electrophoresis (PFGE) was used to subtype the pathogenic bacteria.

  Results  A total of 87 persons developed diarrhea or other symptoms. Two Shiga toxin-producing Escherichia coli strains were isolated from the stool samples of a diarrheal patient and the swab of a kitchen worker. The serotypes of the two isolates were identified as O146∶H10, and the two isolates carried stx_1c subtype of Shiga toxin gene and shared same PFGE patterns.

  Conclusion  This food poisoning outbreak was associated with Shiga toxin-producing E. coli O146∶H10. This was the first report of food poisoning outbreak caused by non-O157 Shiga toxin-producing E. coli in China.