Aims: The study objective was to characterize and analyse the distribution of enterotoxins and genes encoding enterotoxins in Staphylococcus aureus strains recovered from the 601 environment and ingredient samples obtained during multiple inspections of a bakery implicated in two separate staphylococcal food poisoning incidents.
Methods and results: Staphylococcus aureus isolates were evaluated using serological assays for identification of classical staphylococcal enterotoxins (SEs) SEA-SEE and polymerase chain reaction for the detection of newly described SE and SE-like enterotoxin genes seg-seu. Pulsed field gel electrophoresis identified thirteen pattern types. During these investigations, a total of 585 environmental swabs and 16 raw ingredient samples were collected by investigators, 85 of which were confirmed to contain Staph. aureus; of those isolates, 95·3% (81/85) harboured enterotoxin genes and 4·7% (4/85) carried newly described SE and SE-like enterotoxin genes in the absence of classical enterotoxins.
Conclusions: Our research demonstrates the prevalence and diversity of classical SEs and the probable underestimated impact of nonclassical SE and SE-like enterotoxins role in domestic staphylococcal food poisoning outbreaks.
Significance and impact of the study: Given the abundance of SEs and SE-like toxins, these findings illustrate the utilization of PCR for enterotoxin gene identification and its significance in outbreak investigations.
Keywords: PFGE; Staphylococcus aureus; food safety; multiplex PCR; staphylococcal enterotoxins.
Published 2014. This article is a U.S. Government work and is in the public domain in the USA.