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Updated: Nov 15, 2025
Methodology for the Study of Horizontal Gene Transfer in Staphylococcus aureus
Published on: March 10, 2017
Examination of Staphylococcus aureus Prophages Circulating in Egypt
Adriana Ene1, Taylor Miller-Ensminger1, Carine R Mores2
1Bioinformatics Program, Loyola University Chicago, Chicago, IL 60660, USA.
Abstract:
Staphylococcus aureus infections are of growing concern given the increased incidence of antibiotic resistant strains. Egypt, like several other countries, has seen alarming increases in methicillin-resistant S. aureus (MRSA) infections. This species can rapidly acquire genes associated with resistance, as well as virulence factors, through mobile genetic elements, including phages. Recently, we sequenced 56 S. aureus genomes from Alexandria Main University Hospital in Alexandria, Egypt, complementing 17 S. aureus genomes publicly available from other sites in Egypt. In the current study, we found that the majority (73.6%) of these strains contain intact prophages, including Biseptimaviruses, Phietaviruses, and Triaviruses. Further investigation of these prophages revealed evidence of horizontal exchange of the integrase for two of the prophages. These Egyptian S. aureus prophages are predicted to encode numerous virulence factors, including genes associated with immune evasion and toxins, including the Panton-Valentine leukocidin (PVL)-associated genes lukF-PV/lukS-PV. Thus, prophages are likely to be a major contributor to the virulence of S. aureus strains in circulation in Egypt.
Insights
Egyptian Staphylococcus aureus strains frequently carry prophages, which are mobile genetic elements. These prophages contribute to virulence by encoding toxins and immune evasion genes, exacerbating antibiotic-resistant infections.
Area of Science:
- Microbiology
- Genomics
- Infectious Diseases
Background:
- Antibiotic resistance in Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), is a growing global health concern.
- Egypt has observed a significant rise in MRSA infections, necessitating further investigation into the genetic factors driving virulence and resistance.
- Mobile genetic elements, such as bacteriophages, are known to facilitate the acquisition of resistance and virulence genes in bacteria.
Purpose of the Study:
- To investigate the presence and characteristics of prophages in Staphylococcus aureus strains from Egypt.
- To identify potential virulence factors encoded by these prophages.
- To understand the role of prophages in the pathogenicity of circulating S. aureus strains in Egypt.
Main Methods:
- Whole-genome sequencing of 56 S. aureus isolates from Alexandria, Egypt, combined with 17 publicly available Egyptian S. aureus genomes.
- Bioinformatic analysis to identify intact prophages and their genetic content.
- Comparative genomics to detect horizontal gene exchange, specifically integrase genes.
Main Results:
- The majority (73.6%) of sequenced Egyptian S. aureus strains harbored intact prophages, including Biseptimaviruses, Phietaviruses, and Triaviruses.
- Evidence of horizontal exchange of integrase genes was found in two distinct prophage types.
- These prophages are predicted to encode significant virulence factors, including immune evasion genes and toxins like Panton-Valentine leukocidin (PVL).
Conclusions:
- Prophages are prevalent in Egyptian Staphylococcus aureus strains and likely play a substantial role in their virulence.
- The genetic content of these prophages, including virulence factors, contributes to the pathogenicity of S. aureus in Egypt.
- Understanding prophage-mediated virulence is crucial for combating S. aureus infections in the region.
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