Genomic Characterization of Methicillin-Resistant Staphylococcus aureus (MRSA) by High-Throughput Sequencing in a...

Area of Science:

• Microbiology
• Genomics
• Epidemiology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses significant clinical challenges, particularly in healthcare settings.
• In Egypt, MRSA accounts for over 70% of Staphylococcus aureus healthcare-associated infections, highlighting a critical public health concern.

Purpose of the Study:

• To characterize the genomic features, including phylogeny, resistome, and virulome, of clinical MRSA isolates in Egypt.
• To investigate potential genotype-phenotype-clinical outcome correlations within these MRSA strains.

Main Methods:

• Whole-genome sequencing was employed to analyze 18 clinical MRSA isolates.
• Bioinformatics and statistical analyses were used to identify sequence types (STs), SCCmec types, and virulence gene profiles.
• Phylogenetic analysis was conducted to determine genetic relatedness among isolates.

Main Results:

• The ST1535-V clone was the most prevalent MRSA type (16.6%), followed by ST5-VI, ST1-V, and ST239-III (11.1% each).
• SCCmec types V, VI, IV, and III were detected, with SCCmec V being the most common (50%).
• Panton-Valentine leukocidin (PVL)-encoding genes were found in four isolates and were associated with non-severe clinical cases.

Conclusions:

• Sequence type (ST) was the primary correlate of MRSA phylogeny and genotypic patterns.
• While disease outcome and infection source did not correlate with specific genotypic patterns, certain genes were associated with non-severe outcomes.
• The findings provide insights into the genetic landscape and epidemiology of MRSA in Egypt, informing targeted control strategies.