A simple identification scheme for coagulase negative staphylococci from bovine mastitis

Area of Science:

• Veterinary Microbiology
• Bacterial Pathogenesis
• Dairy Science

Background:

• Bovine mastitis is a significant economic challenge in the dairy industry.
• Accurate identification of causative agents, particularly coagulase-negative staphylococci (CoNS), is crucial for effective treatment and control.
• Existing identification methods for CoNS can be complex and time-consuming.

Purpose of the Study:

• To develop and validate a simplified yet accurate identification scheme for CoNS species implicated in bovine mastitis.
• To establish a reliable diagnostic tool for veterinary laboratories dealing with mastitis cases.

Main Methods:

• A three-plate test system was employed for bacterial identification.
• Tests included DNase activity on DNA agar and protease activity on calcium caseinate agar.
• Organism sensitivity to novobiocin, desferrioxamine, and fosfomycin was assessed using agar diffusion tests.
• An alternative method replacing protease tests by assessing inhibition of Staphylococcus delta haemolysin was also evaluated.

Main Results:

• The proposed identification scheme effectively differentiated between various CoNS species commonly found in bovine mastitis.
• The three-plate system demonstrated high accuracy and reproducibility.
• Replacing protease tests with Staphylococcus delta haemolysin inhibition assays provided comparable identification results, simplifying the protocol.

Conclusions:

• The developed identification scheme offers a practical and accurate method for species-level identification of CoNS in bovine mastitis cases.
• This approach can aid veterinarians in selecting appropriate antimicrobial therapies, thereby improving mastitis management in dairy herds.
• The modified protocol using haemolysin inhibition presents a valuable alternative for routine diagnostics.