Exploring the virulence potential of immune evasion cluster genes in methicillin-resistant Staphylococcus aureus from...

Area of Science:

• Microbiology
• Infectious Diseases
• Oncology

Background:

• Methicillin-resistant Staphylococcus aureus (MRSA) causes diverse infections and poses a significant threat to cancer patients globally.
• Bacteriophage-encoded immune evasion cluster (IEC) genes are crucial for MRSA virulence and immune system evasion.
• Understanding the genetic basis of MRSA in vulnerable populations like cancer patients is essential for effective treatment and control.

Purpose of the Study:

• To investigate the association between MRSA and specific bacteriophage-encoded IEC genes in cancer and non-cancer patients.
• To identify novel combinations of IEC genes and assess their prevalence in different patient groups.
• To compare the resistance profiles and toxin gene abundance of MRSA isolates from cancer versus non-cancer patients.

Main Methods:

• Collected 168 MRSA isolates from 38 cancer and 130 non-cancer patients.
• Identified MRSA using cefoxitin disc diffusion and confirmed the *mecA* gene via PCR.
• Detected specific IEC genes using singleplex and multiplex PCR techniques.

Main Results:

• No significant association found between MRSA and patient sex or age (p=0.98).
• MRSA isolates showed significant association with pus samples in non-cancer patients and skin swabs in cancer patients (p=0.01).
• The *sea* gene was more prevalent in MRSA from cancer patients (p=0.03), who also exhibited higher multidrug resistance and toxin gene abundance. Two novel IEC patterns (V1 and V2) were identified.

Conclusions:

• MRSA prevalence and characteristics differ between cancer and non-cancer patients, particularly regarding specific toxin genes like *sea*.
• The identification of novel IEC patterns (V1, V2) suggests evolving MRSA clones.
• Enhanced surveillance and control strategies are crucial to mitigate MRSA dissemination in healthcare settings, especially among immunocompromised individuals.