Molecular characterization of Panton-Valentine leukocidin (PVL) toxin-encoding phages from South India

Area of Science:

• Microbiology and Infectious Diseases
• Genomics and Molecular Biology
• Epidemiology of Bacterial Infections

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) poses a significant public health threat due to its increasing prevalence and antibiotic resistance.
• Panton-Valentine leukocidin (PVL) is a key virulence factor associated with severe MRSA infections, particularly community-acquired infections.

Purpose of the Study:

• To investigate the presence and characteristics of the PVL toxin and its encoding phage in MRSA isolates.
• To analyze the genetic variations within the PVL gene and its associated phage sequences.
• To understand the evolutionary dynamics of PVL-positive MRSA lineages and their potential for virulence.

Main Methods:

• Whole genome sequencing was performed on 19 MRSA isolates.
• Analysis included detection of the PVL gene, assessment of PVL gene sequence variation, and identification of PVL-encoding phages.

Main Results:

• Eleven out of 19 MRSA isolates were positive for the PVL gene and exhibited multidrug resistance.
• The ST772-MRSA-V clone was identified as the predominant PVL-positive MRSA.
• All PVL-positive MRSA isolates carried the ΦIND772PVL phage within their genomes.

Conclusions:

• The study elucidates the evolution of a novel lineage of PVL-producing MRSA.
• The findings highlight the emergence of multidrug-resistant, community-acquired MRSA strains with high virulence potential.
• Continuous surveillance of PVL-MRSA is crucial to monitor and mitigate public health risks.