Functional activity of neutrophils from bovine mammary glands infected with Staphylococcus aureus

To test the effect of Staphylococcus aureus infection on mammary neutrophil function, intramammary neutrophils from S. aureus-infected quarters (n = 8), from adjacent uninfected quarters (n = 8) of S. aureus-infected cows, and from quarters (n = 8) of uninfected cows were collected and incubated with S. aureus in vitro. Mean percent neutrophils phagocytizing, number S. aureus per neutrophil, and log10 viable phagocytized S. aureus/ml were: 53.2, 6.4, and 4.72. Differences in function of neutrophils collected from infected and uninfected quarters were not statistically significant. Results indicate that function of neutrophils from S. aureus-infected quarters is similar to function of neutrophils from uninfected quarters.