Identification of potential sources of Staphylococcus aureus in herds with mastitis problems

• Published in: Journal of dairy science 2010-01, Vol.93 (1), p.180-191
• Main Authors: Capurro, A., Aspán, A., Ericsson Unnerstad, H., Persson Waller, K., Artursson, K.
• Format: Article
• Language: English
• Subjects: Animal and Dairy Science; Animal productions; Animals; bacterial contamination; bacterial infections; Biological and medical sciences; bovine mastitis; calves; Cats; Cattle; dairy cows; dairy herds; disease control; disease incidence; disease prevalence; disease reservoirs; Dogs; dry period; Environmental Microbiology; environmental samples; extra-mammary sites; Female; food contamination; Food industries; Food microbiology; Fundamental and applied biological sciences. Psychology; Genotype; heifers; Humans; Husdjursvetenskap; lactation; Mastitis, Bovine - microbiology; milk; Milk - microbiology; Pregnancy; pulsed-field gel electrophoresis; skin; Skin - microbiology; Staphylococcal Infections - microbiology; Staphylococcal Infections - veterinary; Staphylococcus aureus; Staphylococcus aureus - genetics; Staphylococcus aureus - isolation & purification; strain differences; Terrestrial animal productions; Vertebrates; Veterinary Science; Veterinärmedicin
• ISSN: 0022-0302; 1525-3198; 1525-3198
• DOI: 10.3168/jds.2009-2471

Staphylococcus aureus is a common udder pathogen of dairy cows that often causes herd problems. Various mastitis control programs have been used to combat the problem but have not always been efficient in preventing new Staph. aureus infections, indicating the presence of possible sources of infection other than those traditionally considered. Therefore, the aim of the study was to identify potential sources of infection relevant for Staph. aureus mastitis within 5 dairy herds with udder health problems caused by Staph. aureus. Samples were collected from milk of lactating cows, from body sites, and from the environment of lactating cows, dry cows, late pregnant heifers, young heifers 4 to 12 mo old, and heifer calves 0 to 3 mo old. Isolates of Staph. aureus were identified and compared using pulsed-field gel electrophoresis. Four to 7 unique Staph. aureus pulsotypes were found within each herd, with one strain predominating in milk in each herd. The milk pulsotypes were also frequently isolated in body samples, especially on hock skin, and in the immediate environment of lactating cows, and were sometimes found in other animal groups, especially in dry cows and heifer calves 0 to 3 mo old. The prevalence of Staph. aureus in milk and other types of samples varied markedly between herds. Staphylococcus aureus isolates with genotypes indistinguishable from those found in milk also dominated in extra-mammary sites within the dairy herds studied, and hock skin was identified as an important reservoir of Staph. aureus. The results contribute new knowledge necessary to improve strategies for udder health control in herds.