Protein A in Staphylococcus intermedius isolates from dogs and cats

Area of Science:

• Microbiology
• Veterinary Science
• Immunology

Background:

• Staphylococcus intermedius is a common pathogen in dogs and cats.
• Protein A is a surface protein found in some Staphylococcus species, known for its immunoglobulin-binding properties.
• Understanding the presence and quantity of Protein A in S. intermedius is crucial for veterinary diagnostics and research.

Purpose of the Study:

• To determine the presence and quantity of extracellular and cell-bound Protein A in Staphylococcus intermedius isolates from dogs and cats.
• To compare the levels of extracellular and cell-bound Protein A.
• To investigate the potential for removing extracellular Protein A.

Main Methods:

• An enzyme-linked immunoglobulin-binding assay was employed to quantify Protein A.
• Whole cell and supernatant fractions of 139 S. intermedius isolates were analyzed.
• A protein A-producing strain of S. aureus and a protein A-deficient strain of S. epidermidis were used as controls.

Main Results:

• Extracellular Protein A was detected in 84.9% (118/139) of S. intermedius isolates.
• The majority of these isolates (58.5%) produced over 0.2 micrograms of extracellular Protein A per ml.
• Cell-bound Protein A was found in only 4.3% (6/139) of isolates, with most also producing significant extracellular Protein A.
• Over 96% of extracellular Protein A was removable via immunoglobulin G-adsorbed agarose gel.

Conclusions:

• The majority of Staphylococcus intermedius isolates from dogs and cats produce significant amounts of extracellular Protein A.
• Cell-bound Protein A is less common and typically present in lower quantities compared to extracellular Protein A in these isolates.
• Extracellular Protein A can be effectively removed using immunoglobulin G-based adsorption techniques.