An IgG-binding protein A homolog in Staphylococcus hyicus

Area of Science:

• Microbiology
• Molecular Biology
• Veterinary Science

Background:

• Staphylococcus hyicus causes exudative epidermitis in pigs and mastitis in cattle.
• Staphylococcal protein A (SpA) is a key virulence factor in Staphylococcus aureus, known for its IgG-binding properties.

Purpose of the Study:

• To identify and characterize a staphylococcal protein A homolog in Staphylococcus hyicus.
• To investigate the presence and variation of the spa gene in clinical isolates of S. hyicus.

Main Methods:

• Shotgun phage display was employed to identify the protein A homolog.
• Polymerase Chain Reaction (PCR) was used to detect the spa gene in clinical isolates.
• Sequence analysis was performed on PCR amplicons to determine variations in the spa gene.

Main Results:

• A staphylococcal protein A homolog was identified in Staphylococcus hyicus with an YSIRK-type signal peptide, IgG-binding domains, and cell wall anchoring motif.
• The identified protein showed highest similarity to Staphylococcus pseudintermedius protein A but lacked typical Xr polypeptide repeats.
• The spa gene was detected in all ten porcine and eight bovine clinical isolates, with amplicons of two different sizes, indicating variations in IgG-binding domains.

Conclusions:

• The study successfully identified a staphylococcal protein A homolog in S. hyicus, contributing to the understanding of its potential virulence.
• Variations in the spa gene, specifically the number of IgG-binding domains, were observed in clinical isolates, suggesting adaptation or strain diversity.
• The presence of the spa gene in S. hyicus provides insights into the bacterium's pathogenic mechanisms and host interactions.