Characterization of an Unusual Foodborne Illness Including an Outbreak and Sporadic Illness Caused by Three Bacterial Pathogens Via a Takeaway Service

Abstract

Takeaway food services are an emerging business in China and have a potential impact on food safety. An unusual foodborne illness associated with takeaway food delivered through a logistics company on August 27, 2018 is reported. Epidemiological investigations showed that 28 patients from 2 companies were diagnosed with gastroenteritis symptoms. The major symptoms included nausea (24, 85.71%), vomiting (24, 85.71%), diarrhea (22, 78.57%), and abdominal pain (22, 78.75%). Laboratory investigations showed that six <i>Staphylococcus aureus</i> isolates, three <i>Salmonella enteria serovar livingstone</i> isolates, and one <i>Vibrio parahaemolyticus</i> isolate were detected. Six <i>S. aureus</i> isolates were detected from one patient, food, and a food handler, and all six <i>S. aureus</i> isolates had the same pulsed-field gel electrophoresis (PFGE) pattern and multilocus sequence typing (MLST) genotype. Staphylococcal enterotoxin A was detected from food and the six <i>S. aureus</i> isolates. These results confirmed that <i>S. aureus</i> isolates were the major agent causing this foodborne illness. Three <i>Salmonella</i> isolates with the same PFGE pattern and MLST genotype were detected from patients. This was the first time that <i>Salmonella</i> isolates have been identified as causing a foodborne disease outbreak in China. Only one O4:K8 serotype of <i>V. parahaemolyticus</i> with the <i>tdh</i> gene isolate was detected from one patient. These results confirmed that this was an unusual foodborne illness that included an outbreak associated with two different pathogens and a third pathogen sporadic illness. Takeaway services pose a risk to public health because they have the potential to distribute contaminated products over a large geographic area within a short time. Therefore, more attention should be paid to prevent and control foodborne illnesses caused by contaminated food from takeaway services.