Identification of clumping-factor-negative staphylococci isolated from cows' udders

Area of Science:

• Veterinary Microbiology
• Bacteriology

Background:

• Bovine mastitis and teat canal infections are often caused by Gram-positive cocci.
• Accurate identification of bacterial species is crucial for understanding pathogenesis and developing effective treatments.

Purpose of the Study:

• To identify Staphylococcus species isolated from cow teats and milk.
• To characterize an unidentified group of Staphylococcus-like bacteria.

Main Methods:

• Isolation and cultivation of 954 Gram-positive cocci from bovine teat and milk samples.
• Biochemical testing including catalase, clumping factor, and beta-haemolysin assays.
• Species-level identification using standard microbiological techniques.

Main Results:

• 87% of isolates identified as known Staphylococcus species (S. xylosus, S. epidermidis, S. sciuri, S. haemolyticus, S. hyicus, S. simulans, S. cohnii).
• 9% of isolates belonged to an unidentified group of Staphylococcus-like bacteria.
• Enhanced growth observed in some strains with fatty substances added to media.
• Only 9 strains were classified as Micrococcus.

Conclusions:

• The majority of coagulase-negative staphylococci from cows' milk belong to known species.
• A distinct group of unidentified Staphylococcus-like bacteria warrants further investigation.
• A proposed identification scheme for coagulase-negative staphylococci in bovine milk.