|CARRICA, JAOA - Biomerieux, Inc|
|MACHADO, MIGUEL - Biomerieux, Inc|
|BAILEY, STAN - Biomerieux, Inc|
|DUTTA, VIKRANT - Biomerieux, Inc|
Submitted to: Letters in Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2023
Publication Date: 7/28/2023
Citation: Mcmillan, E.A., Hiott, L.M., Carrica, J.A., Machado, M.P., Bailey, S.J., Dutta, V., Jackson, C.R., Frye, J.G. 2023. Polymerase Chain Reaction for the in vitro detection of the pESI plasmid associated with the globally circulating Salmonella Infantis outbreak strain. Letters in Applied Microbiology. https://doi.org/10.1093/lambio/ovad088.
Interpretive Summary: Salmonella is a human bacterial pathogen that can cause foodborne illnesses and outbreaks, some of which can be attributed to poultry meat sources. There are more than 2,500 serotypes of Salmonella, however, these serotypes vary in prevalence among poultry meat samples. Recently, S. Infantis has been detected more frequently in samples from chicken and turkey meat. It has been determined that most of the S. Infantis being detected carry a novel DNA plasmid called pESI. Detecting this plasmid and confirming the Infantis serotype is important for epidemiological investigations and for poultry producers monitoring production. We have developed a polymerase chain reaction allowing for the detection of the pESI plasmid with three targets and one to confirm the Infantis serotype. PCR primers were analyzed bioinformatically by comparison to a database of Salmonella genome sequences. The primers were found to have greater than 95% precision, specificity, and sensitivity. Additionally, all isolates tested in vitro produced a band of the expected size. This tool provides a fast and easy alternative to whole genome sequencing to detect pESI and Salmonella Infantis.
Technical Abstract: A globally circulating strain of Salmonella enterica serotype Infantis containing the pESI plasmid has increased in prevalence in poultry meat samples and cases of human infections. In this study, a PCR protocol was designed to detect the pESI plasmid and confirm the Infantis serotype of Salmonella isolates. Primers were tested bioinformatically to predict specificity, sensitivity, and precision. Fifty-four isolates of Salmonella serotypes Infantis, Senftenberg, and Alachua were tested, with and without the pESI plasmid carriage. Isolates of 31 additional serotypes were also screened to confirm specificity to Infantis. Specificity, sensitivity, and precision of each primer was greater than 0.95. All isolates tested produced the expected band sizes. This PCR protocol provides a rapid and clear result for the detection of the pESI plasmid and serotype Infantis and will allow for the in vitro detection for epidemiological studies where whole genome sequencing is not available.