Loading...
Genome-Wide Profiling of Enterotoxigenic Staphylococcus aureus Strains Used for the Production of Naturally Contaminated Cheeses
Citations
Altmetric:
Date
2019-12-27
Collections
Files
Loading...
main article
Adobe PDF, 3.21 MB
Research Projects
Organizational Units
Journal Issue
Citation
Macori, G.; Bellio, A.; Bianchi, D.M.; Chiesa, F.; Gallina, S.; Romano, A.; Zuccon, F.; Cabrera-Rubio, R.; Cauquil, A.; Merda, D.; Auvray, F.; Decastelli, L. Genome-Wide Profiling of Enterotoxigenic Staphylococcus aureus Strains Used for the Production of Naturally Contaminated Cheeses. Genes 2020, 11, 33. https://doi.org/10.3390/genes11010033
Abstract
Staphylococcus aureus is a major human pathogen and an important cause of livestock
infections. More than 20 staphylococcal enterotoxins with emetic activity can be produced by specific
strains responsible for staphylococcal food poisoning, one of the most common food-borne diseases.
Whole genome sequencing provides a comprehensive view of the genome structure and gene content
that have largely been applied in outbreak investigations and genomic comparisons. In this study, six
enterotoxigenic S. aureus strains were characterised using a combination of molecular, phenotypical
and computational methods. The genomes were analysed for the presence of virulence factors (VFs),
where we identified 110 genes and classified them into five categories: adherence (n = 31), exoenzymes
(n = 28), genes involved in host immune system evasion (n = 7); iron uptake regulatory system
(n = 8); secretion machinery factors and toxins’ genes (n = 36), and 39 genes coding for transcriptional
regulators related to staphylococcal VFs. Each group of VFs revealed correlations among the six
enterotoxigenic strains, and further analysis revealed their accessory genomic content, including
mobile genetic elements. The plasmids pLUH02 and pSK67 were detected in the strain ProNaCC1 and
ProNaCC7, respectively, carrying out the genes sed, ser, and selj. The genes carried out by prophages
were detected in the strain ProNaCC2 (see), ProNaCC4, and ProNaCC7 (both positive for sea). The
strain ProNaCC5 resulted positive for the genes seg, sei, sem, sen, seo grouped in an exotoxin gene
cluster, and the strain ProNaCC6 resulted positive for seh, a transposon-associated gene. The six
strains were used for the production of naturally contaminated cheeses which were tested with the
European Screening Method for staphylococcal enterotoxins. The results obtained from the analysis of
toxins produced in cheese, combined with the genomic features represent a portrait of the strains that
can be used for the production of staphylococcal enterotoxin-positive cheese as reference material.