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Updated: May 22, 2026
07:10
A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
Elevated enterotoxin A expression and formation in Staphylococcus aureus and its association with prophage induction
Rong Cao1, Nikoleta Zeaki, Nina Wallin-Carlquist
1Applied Microbiology, Department of Chemistry, Faculty of Engineering, Lund University, Lund, Sweden.
Applied and Environmental Microbiology
|May 1, 2012
Summary
Bacterial strains producing staphylococcal enterotoxin A (SEA) were categorized by production levels. High-producing strains, particularly those with inducible phages, are more linked to food poisoning risks.
Area of Science:
- Microbiology
- Molecular Biology
- Food Safety
Background:
- Staphylococcus aureus produces staphylococcal enterotoxin A (SEA), a key factor in food poisoning.
- SEA production varies significantly among different bacterial strains.
- The genetic basis for this variation, particularly phage-encoded SEA, is not fully understood.
Purpose of the Study:
- To investigate the correlation between SEA production levels and the genetic characteristics of SEA-encoding phages in Staphylococcus aureus.
- To determine the role of prophage induction in enhancing SEA production.
- To identify specific phage lineages associated with high SEA production.
Main Methods:
- Categorization of Staphylococcus aureus strains into high- and low-SEA-producing groups based on quantified SEA levels.
- Analysis of sea gene expression and identification of sea(1) and sea(2) variants.
- Sequencing of Siphoviridae phage regions to identify clonal lineages.
- Treatment with mitomycin C (MC) to induce prophages and assess its effect on SEA production.
Main Results:
- SEA production levels correlated with the expression of sea variants (sea(1) vs. sea(2)).
- Two distinct clonal lineages were identified within high-SEA-producing strains.
- Prophage induction via mitomycin C significantly increased SEA levels (up to 10-fold) in specific strains, linked to phage-activated sea transcription.
- Low-SEA-producing strains and a subgroup of high-SEA-producers showed no SEA increase upon MC treatment.
Conclusions:
- SEA expression in enterotoxigenic Staphylococcus aureus is strongly linked to the clonal lineage of the carrying phages.
- High-SEA-producing strains, especially those with inducible sea(1) phages, represent a greater risk for staphylococcal food poisoning.
- The capacity for prophage induction is a critical factor determining the potential for massive SEA production.
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