Evaluation of the immune response induced by two Staphylococcus aureus strains with different genotype and adaptability to the bovine mammary gland in an experimental infection

ENGLER C; RENNA MS; BECCARIA C; SILVESTRINI P; SIMONUTTI V; BARAVALLE C; CALVINHO LF; DALLARD B

Mar del Plata

Congreso; Reunión Conjunta SAIC, SAI, AAFE, NANOMED Argentina 2021; 2021

The aim of this study was to evaluate and compare the ability of two S. aureus strains with different adaptation genotypes (low and high) to the bovine mammary gland (MG) to induce immune response after an experimental intramammary infection (IMI). Three animals were challenged in two mammary quarters with S. aureus 806 strain (non-persistent NP) or 5011 strain (persistent P), and three animals were inoculated in two mammary quarters with saline solution (control group). Milk samples were collected at 0, 0.5, 1, 2, 3, 4, 7, 14 and 21 days post inoculation(pi) and bacteriological and quality milk examination, somatic cell count (SCC), nitrite, lactoferrin (Lf) and cytokines levels (IL-1β, IL-6 and IL-4) were evaluated. The NP strain (806) was able to induce mild clinical mastitis, triggering a rapid and effective inflammatory response to control IMI. The P strain (5011) was able to induce a subclinical IMI, triggering a less and later inflammatory response than the NP strain. A significant effect of infection was observed in SCC and nitrites concentration over time (p