Staphylococcal Poisoning Foodborne Outbreak: Epidemiological Investigation and Strain Genotyping

Abstract

In June 2011, an outbreak of Staphylococcus aureus enterotoxin food poisoning gastroenteritis occurred in Turin, Italy, following a catered dinner party at a private home. Within a few hours, 26 of the 47 guests experienced gastrointestinal illness, and 9 were hospitalized. A retrospective cohort study using a standardized questionnaire was carried out, and the risk ratios for each food item were calculated. The analysis indicated consumption of seafood salad as the most probable cause of the outbreak (risk ratio = 11.72; 95 % confidence interval, 1.75 to 78.54). Biological samples were collected from four of the hospitalized guests (stool and vomit), nasal mucosa swabs from three food handlers employed with the caterer, and available food residuals. All stool and vomit samples tested positive for enterotoxigenic S. aureus. As residues of the seafood salad were no longer available for sampling, suspected contamination could not be verified. However, no other food was found contaminated by S. aureus or its enterotoxins. All isolates from the biological samples were characterized at the genomic level by means of two multiplex PCR protocols to determine the presence of genes encoding staphylococcal enterotoxins, pulsed-field gel electrophoresis and staphylococcal protein A gene (spa) typing to describe their genetic profiles. All the isolates presented genes encoding SEA and SEI; the pulsed-field gel electrophoresis genetic profiles revealed the same pulsotype in the microorganism isolated from the hospitalized guests as in one of the isolates from a food handler's nasal mucosa, and the spa typing analysis reported two closely related spa types (t701 and t267), implicating the food handler as the most likely outbreak source.

Investigation of a Staphylococcal Food Poisoning Outbreak from a Chantilly Cream Dessert, in Umbria (Italy)

“…Furthermore, this outbreak underlines the usefulness of complying with the fundamental principles of Good Hygienic Practices and Good Manufacturing Practices guidelines for preventing FBOs due to SEs (Gallina et al , 2013). Food handlers should be properly trained in food hygiene procedures, to understand the importance of sanitation and cleanliness of kitchen equipment and the maintenance of the cold chain during food production and storage (Schmid et al , 2007).…”

“…To date, 23 SEs have been reported in literature (Ono et al , 2015). The presence of a S. aureus enterotoxigenic strain in the nasopharyngeal or oropharyngeal tract of a food handler is frequently associated with FBOs (Todd et al , 2008; Todd et al , 2010; Gallina et al , 2013). Food poisoning occurs after the ingestion of food contaminated with enterotoxins produced by S. aureus ; the onset of symptoms occurs a few hours (2–8) after ingestion of the contaminated food and improper preparation, handling, or storage (Schelin et al , 2011).…”

Staphylococcus aureus and Methicillin-Resistant Staphylococcus aureus in Workers in the Food Industry

“…In 2013, Johler et al investigated an SFP outbreak caused by an enterotoxin A and egc-cluster positive strain of CC30 that was also found in the nose of a food handler. Another SFP outbreak reported recently was caused by an enterotoxin A and I producing strain, which was introduced most likely by a food handler (Gallina et al, 2013). Similarly, Wei et al were able to trace back enterotoxigenic outbreak strains carrying sea and seb, respectively, to the hand lesion of a food handler in a cafeteria (Wei and Chiou, 2002).…”

Staphylococcus aureus ST6-t701 Isolates from Food-Poisoning Outbreaks (2006–2013) in Xi'an, China

“…In recent years, an increasing number of foodborne poisonings with S. aureus multilocus sequence type (ST) 6 and/or spa type (t701) have been reported in Shenzhen and Ma'anshan, China (Wang et al, 2011;Yan et al, 2012), and Turin, Italy (Gallina et al, 2013), Korea (Cha et al, 2006;Hyeon et al, 2013), and Japan Suzuki et al, 2014). We described five foodborne poisoning outbreaks with S. aureus ST6-t701 in the Xi'an city of China during an 8-year period (2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013).…”