Long-term Persistence of Genetic Types of Mastitis-causing Staphylococcus aureus on Three Dairy Herds

Staphylococcus aureus remains a significant cause of mastitis in the dairy industry. It has been recommended that control of S. aureus mastitis be focused on the specific genetic types of S. aureus that most commonly cause the mastitis. Genetic types can be defined using molecular techniques, including pulsed field gel electrophoresis (PFGE). There have been comparatively few studies looking at within-herd persistence over time of S. aureus genetic types as causes of mastitis. Most have dealt with very few isolates or comparatively short periods of time. The objective of this investigation was to examine PFGE band patterns (EPs) from bovine mastitis-causing S. aureus isolates from three related herds over the course of 15 years to determine if any patterns persisted long-term.