Staphylococcus aureus associated with mammary glands of cows: genotyping to distinguish different strains among herds.
The hypothesis that strains of Staphylococcus aureus are more likely to be unique to a herd than common to several herds was tested. Herds (n=28) from nine geographic areas of Korea, with elevated milk somatic cell counts (>500000 cells/ml) were enrolled in this study. Mammary quarter milk samples were aseptically collected from all lactating cows (n=616) with at least three functional quarters. Milk was cultured and S. aureus isolates were typed using pulse field gel electrophoresis of DNA SmaI digests. A total of 181 cows were identified as having S. aureus intramammary infections. A total of 52 different types of S. aureus were identified and 34 (65.4%) were associated with a single herd. A total of 18 types of S. aureus were found in multiple herds; 14 types were found in two herds, and four types were found in three herds. Herds with 1, 2, 3, and more than 3 types, were: four (14.3%); eight (28.6%); nine (32.1%); and seven (25.0%). The data indicate that the majority of strains were found in one herd only, and more than 90% were found in two or less herds, suggesting that strains of S. aureus are more likely to be restricted to a single herd, than found in multiple herds.
Joo
Y S
YS
Mastitis Research Laboratory, Bacteriology and Immunology Department, National Veterinary Research Institute, Kyunggi-do, South Korea.
Fox
L K
LK
Davis
W C
WC
Bohach
G A
GA
Park
Y H
YH
D000818:Animals; D001940:Breast / Q000382:microbiology*; D002417:Cattle / Q000382:microbiology*; D003612:Dairying; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D005260:Female; D005838:Genotype; D013211:Staphylococcus aureus / Q000145:classification / Q000302:isolation & purification*