S taphylococcus aureus Outbreak Investigation of an I llinois Bakery

Over 100 individuals were sickened after ingesting an assortment of desserts linked to four staphylococcal food poisoning outbreaks leading investigators to products manufactured by an I llinois bakery. The investigative team identified substantial deviations from the current G ood M anufacturing P ractice R egulations, 21 CFR Part 110, during multiple visits to the bakery. A total of 299 environmental swabs and 16 raw ingredients were collected for bacteriological analysis. S taphylococcus aureus isolates recovered from these samples were evaluated using either serological or polymerase chain reaction methods for the identification of staphylococcal enterotoxins SEA‐SEE , SEG‐SEI , SE ‐like SElJ ‐ SElU or their respective genes, and for Panton–Valentine leukocidin cytotoxin. A raw ingredient and 16% of the environmental samples revealed the presence of enterotoxigenic S . aureus capable of producing diverse combinations of toxins. Antimicrobial susceptibility testing found that all S . aureus isolates were resistant to one or more agent(s). Pulsed field gel electrophoresis characterization of the isolates identified six pattern types. Practical Applications This S taphylococcus aureus outbreak investigation revealed the prevalence and diversity of antimicrobial‐resistant strains of S . aureus carrying both classical staphylococcal enterotoxins ( SE s) and genes for nonclassical SE and SE ‐like enterotoxins found in the environment of an I llinois bakery. In this occurrence, nonclassical SE and SE ‐like enterotoxin serotypes were coupled with classical SE s, and therefore detectable by commercially available kits. This outbreak investigation demonstrated the abundance of the nonclassical SE and SE ‐like enterotoxin serotypes in the environment and the anticipated need for new screening method requirements.