Etiological diagnosis and traceability analysis of a food poisoning caused by Staphylococcus aureus

Abstract

ObjectiveTo investigate the etiological features and traceability of a food poisoning incident in Pudong District， Shanghai， and to provide a basis for the future investigation and disposal of similar incidents.MethodsAnal swabs of the patients and a chef and food residues were collected for pathogens isolation and identification. Enterotoxin detection immunosorbent assay （ELISA）， drug sensitivity test， pulsed field gel electrophoresis （PFGE） and multilocus sequence typing （MLST） were used for genotyping and tracing.ResultsNine anal swabs from patients， one anal swab from the chef， and 3 food residues were positive for Staphylococcus aureus （S. aureus）. Ten isolates from patients and the chef carried Staphylococcus enterotoxin （SE） A and SEE， while 3 isolates from food carried SEA， SED and SEE. All the isolates were resistant to penicillin. The S. aureus strains from the case shared the same PFGE pattern and the MLST type of them belonged to ST6.ConclusionThe cause of this food poisoning outbreak was S. aureus contamination. It is necessary to further strengthen the education and management of food processing enterprises， canteens， etc. to prevent similar incidents.

Keywords

• food poisoning
• staphylococcus aureus
• enterotoxins
• drug susceptibility test
• molecular typing