Staphylococcus aureus seroproteomes discriminate ruminant isolates causing mild or severe mastitis

Area of Science:

• Veterinary Microbiology
• Immunology
• Bacterial Pathogenesis

Background:

• Staphylococcus aureus is a primary cause of ruminant mastitis.
• Mastitis severity in ewes ranges from subclinical to gangrenous.
• Factors influencing S. aureus mastitis outcomes remain unclear.

Purpose of the Study:

• To identify Staphylococcus aureus immunoreactive proteins associated with mild versus severe ewe mastitis.
• To define the core and accessory seroproteomes of S. aureus strains causing mastitis.
• To investigate the distribution of mastitis-severity-specific proteins in other S. aureus strains.

Main Methods:

• Experimental mastitis induced in ewes using S. aureus strains from gangrenous (O11) and subclinical (O46) cases.
• SERological Proteome Analysis (SERPA) using ewe sera to identify immunoreactive proteins.
• Comparative analysis of protein profiles between mild and severe mastitis-inducing strains.

Main Results:

• Two S. aureus strains induced distinct mastitis phenotypes (mild with O46, severe with O11) in ewes.
• SERPA identified 89 immunoreactive proteins, with 74 in the core seroproteome.
• An accessory seroproteome of 15 proteins was identified, including 12 specific to the severe strain (O11) and 3 to the mild strain (O46).

Conclusions:

• This study first identifies common and strain-specific immunogenic proteins in S. aureus causing mild or severe mastitis.
• These identified proteins are crucial for understanding S. aureus virulence and host-pathogen interactions in ruminant mastitis.
• Findings provide new targets for diagnostic and therapeutic strategies against S. aureus mastitis.