Immune response in nonspecific mastitis: What can it tell us?

We analyzed a large number of immune response parameters from quarter milk samples with distinct bacteriological and quarter somatic cell count (qSCC) statuses. Furthermore, we sought to explore and identify displayed immune response patterns in milk samples from mammary glands with nonspecific mastitis. Thus, 92 quarter milk samples from 28 cows were stratified into 4 groups, as follows: (1) 49 culture-negative control quarters with a low qSCC (<1 × 105 cells/mL) from 19 dairy cows (so-called healthy quarters); (2) 15 culture-negative quarters with high qSCC (>2 × 105 cells/mL; so-called quarters with nonspecific mastitis) from 10 dairy cows; (3) 8 culture-positive quarters with low qSCC (noninflammatory quarters with low qSCC) from 5 dairy cows; and (4) 20 culture-positive quarters with high qSCC (so-called truly infected quarters) from 8 dairy cows. Using flow cytometry, we evaluated the percentage of milk neutrophils and their viability, intracellular reactive oxygen species production, phagocytosis, and the expression of CD62L, CD11b, and CD44 for each of the 4 quarter strata. Furthermore, the percentage of monocyte/macrophages, B cells, and T lymphocyte subsets were evaluated by flow cytometry. Milk samples from bacteriologically negative quarters (both with a low and elevated qSCC) had a lower qSCC than those with bacteriologically positive outcomes (both with a low and elevated qSCC). As expected, the healthy quarters showed the lowest percentage of neutrophils and also showed a higher percentage of milk monocytes/macrophages and lower percentage of T lymphocytes than truly infected quarters. The most prominent result of the present study is that quarters with nonspecific mastitis showed the highest percentage of milk CD4+ T lymphocytes. The healthy quarters had a lower percentage of apoptotic neutrophils than noninflammatory and truly infected quarters, although it did not differ from those from the quarters with nonspecific mastitis. Our study supports the role of differential cell counting in the diagnosis of mastitis, as the milk leukocyte populations markedly fluctuate under healthy and inflammatory conditions. Furthermore, an increase in milk CD4+ T cells was associated with nonspecific mastitis, suggesting an increase in this leukocyte subpopulation is correlated with low bacterial shedding. Our study allows us to go further in our understanding of mammary gland immunity, providing further insights on potential protective mammary gland immunity, which we hypothesize can open new avenues for the development of novel targets that can promote bovine udder health.

Inhibition of the growth of major mastitis-causing pathogens by non-aureus Staphylococcus isolates using the cross-streaking method / Comunicação: Inibição do crescimento dos principais patógenos causadores de mastite por isolados de estafilococos não aureus pelo método cross-streaking

O objetivo do presente estudo foi avaliar a capacidade de estafilococos não aureus (NAS) isolados de diferentes nichos ecológicos (leite, ambiente e ápice do teto), associados a vacas leiteiras, de inibir os principais agentes etiológicos da mastite bovina (Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis e Escherichia coli). Neste estudo, 38 isolados NAS de diferentes nichos ecológicos foram avaliados quanto à capacidade de inibir o crescimento in vitro de importantes patógenos causadores de mastite pelo método cross-streaking. No total, 19 (50%) isolados de NAS (oito isolados de S. chromogenes, 10 de S. fleurettii e um de S. haemolyticus) apresentaram inibição contra os principais patógenos causadores de mastite. No entanto, a inibição dos patógenos causadores da mastite bovina por isolados de NAS foi maior contra bactérias Gram-positivas. Além disso, o presente estudo não sugeriu que os nichos ecológicos influenciam a capacidade do NAS de inibir os principais patógenos causadores da mastite bovina. Com base nesses resultados, concluiu-se que certos isolados de NAS apresentam potencial efeito protetor contra os principais patógenos da mastite, pelo menos in vitro.(AU)

Efeito do uso de minerais traços (cobre, zinco, selênio e manganês) e vitaminas (A e E) injetáveis sobre o estresse oxidativo e função de neutrófilos de fêmeas da raça Holandesa no período de transição / Effect of use of injected trace minerals (copper, zinc, selenium, and manganese) and vitamins (A and E) on oxidative stress and neutrophil function in females of Hostein cows during transitionl

O objetivo deste estudo foi avaliar o efeito metafilático de minerais traços e vitaminas A e E injetáveis, em parâmetros do estresse oxidativo e na função de neutrófilos em fêmeas da raça Holandesa no período de transição. Sessenta animais foram divididos em dois grupos: animais que receberam minerais traços e vitaminas A e E injetáveis (GMTV) (n= 30) e grupo controle (GC) (n= 30). Não houve diferença significativa entre os grupos nos parâmetros avaliados, porém observou-se diferença significativa entre tratamento e dia para os valores da SOD, com maior atividade dessa enzima em fêmeas GMTV, nas semanas próximas ao parto. Observou-se diferença de dia e para interação tratamento e dia para o TBARS, em que fêmeas GMTV mostraram menores valores de TBARS em todos os momentos, exceto sete dias após o parto. Houve efeito significativo de dia para leucócitos, interação tratamento e dia para neutrófilos e interação tratamento e dia para fagocitose de neutrófilos, em que as fêmeas GMTV apresentaram valores menores de leucócitos e neutrófilos próximo ao parto, além de maior fagocitose de neutrófilos. Pode-se observar que houve melhora no sistema oxidativo e imune de fêmeas GMTV, resposta que provavelmente está relacionada com a administração dos minerais traços e vitaminas A e E.(AU)

This study evaluates the metaphylactic of the subcutaneous administration of a trace minerals and vitamins A and E, on the oxidative stress and neutrophil function in Holsteins cows under the transition period. Sixty females were divided in two groups: group with trace minerals and vitamins (GMTV) (n= 30) and group control (GC) (n= 30). There was no significant difference between those groups; however, we find significant difference between treatment and day for Superoxide dismutase (SOD) values with higher activity of this enzyme in females GMTV on the weeks next to the parturition. Still, there was difference on day and, for interactions between treatment and day for TBARS, were females GMTV showed lower values of TBARS in all moments, except on day seven after the parturition. For leucocytes, there is a significant effect by day, interaction on treatment and day on neutrophils, and interaction treatment and day for neutrophil phagocytosis, were females GMTV showed lower values of leucocytes and neutrophils next to the parturition, and an increase of neutrophils phagocytosis. In summary, cows from the GMTV group had an improvement on the immune and oxidative systems, probably correlated with the administration of this supplement.(AU)