Experimental <i>Staphylococcus aureus</i> Mastitis Infection Model by Teat Dipping in Bacterial Culture Suspension in Dairy Cows

• Main Authors: Oudessa Kerro Dego, Paulina A. Pacha, Barbara E. Gillespie, Gina M. Pighetti
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Animals
• Subjects: experimental infection; <i>Staphylococcus aureus</i>; bovine mastitis; intramammary infection model; teat dipping; bacterial culture suspension
• Online Access: https://www.mdpi.com/2076-2615/10/5/751

Mastitis is inflammation of mammary glands usually caused by bacteria such as <i>Staphylococcus aureus</i>. Dairy cows are susceptible to mastitis during early dry and transition periods. Effective vaccine is needed during these periods. One of the limitations to develop an effective vaccine against <i>S. aureus</i> is the absence of good infection model. Intramammary infusion (IMIF) with <i>S. aureus</i> has been used as an infection model to test vaccine efficacy. IMIF is reliable in causing mastitis, but it bypasses physical barriers, non-specific natural defenses, and immunity in the teat canal. IMIF also transfers a large number of bacteria into the intramammary area at once. The objective of this study was to develop <i>S. aureus</i> IMIF model that mimics natural infection. Eight Holstein dairy cows were randomly divided into two groups of experimental (<i>n</i> = 5) and control (<i>n</i> = 3) cows. All teats of experimental cows were dipped in <i>S. aureus</i> culture suspension, whereas that of control cows were dipped in phosphate-buffered saline. Results showed that four of five cows were infected with challenge strain by day 3 of the challenge. The remaining cow was infected with <i>Staphylococcus chromogenes.</i> In conclusion, an experimental <i>S. aureus</i> intramammary infection can be induced by teat dipping into bacterial suspension.