Comparative genomics and DNA array-based genotyping of pandemic Staphylococcus aureus strains encoding...

Area of Science:

• Microbiology
• Epidemiology
• Molecular Biology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) strains producing Panton-Valentine leukocidin (PVL) have emerged globally.
• These epidemic PVL-MRSA strains are linked to a limited number of distinct clonal lineages.

Purpose of the Study:

• To develop and validate a novel DNA microarray assay for simultaneous detection of virulence factors, resistance genes, and agr types in MRSA.
• To characterize major pandemic PVL-MRSA lineages and investigate their genetic diversity and evolutionary origins.

Main Methods:

• A multiplex linear DNA amplification and microarray hybridization assay was developed.
• The assay was used in conjunction with multilocus sequence typing (MLST) and spa typing.
• 56 clinical isolates and reference strains representing pandemic PVL-MRSA lineages were analyzed.

Main Results:

• The microarray assay successfully assigned isolates to clonal groups, consistent with MLST and spa typing.
• Ten distinct clonal groups of PVL-MRSA were identified, encompassing 12 MLST types.
• Analysis revealed diverse genetic backgrounds for pandemic PVL-MRSA strains, offering insights into lineage evolution.

Conclusions:

• The DNA microarray technique is a valuable epidemiological tool for detailed characterization of clinical MRSA isolates.
• This method facilitates global strain comparison and enhances understanding of PVL-MRSA epidemiology.
• The study highlights the diverse genetic origins contributing to the spread of pandemic PVL-MRSA.