Characterization of an incipient granulosa cell tumour in a Holstein cow: Steroid hormone receptors and coregulators expression.

The objective of this study was to describe a case of a granulosa cell tumour (GCT) of incipient formation and to characterize it by its immunohistochemical pattern and hormonal profile. The case presented corresponds to a 7-year-old Holstein cow without reproductive disorders. No alterations were observed at rectal palpation, neither in the ultrasonography nor in the hormonal profile. A GCT concomitant with normal follicular development was diagnosed. Through a panel of immunohistochemical markers, a highly differentiated pattern could be determined in the GCT, which preserves the expression of steroid receptors (ESR1, ESR2 and PR) typical of granulosa cells, but does not express the enzymes for the synthesis of androgens (CYP17A1) and oestrogens (CYP19A1). In addition, the expression of co-regulators of steroid hormone receptors and neuroendocrine markers was described for the first time in a GCT in cattle. These results increase the information about GCTs in cattle before the ovarian function is compromised.

Capacity of two Staphylococcus aureus strains with different adaptation genotypes to persist and induce damage in bovine mammary epithelial cells and to activate macrophages.

The aim of this study was to evaluate and compare the ability to adhere/internalize, persist, and induce damage in mammary epithelial cells (MAC-T) of two Staphylococcus aureus strains with different adaptation genotypes (low and high) to the bovine mammary gland (MG). Also, the phagocytic and bactericidal capacity induced after the interaction between macrophages, isolated from mammary secretion, of both S. aureus strains was evaluated. Two isolates (designated 806 and 5011) from bovine intramammary infection (IMI) harboring genes involved in adherence and biofilm production, belonging to different capsular polysaccharide (CP) type, accessory gene regulator (agr) group, pulsotype (PT) and sequence type/clonal complex (ST/CC). Strains 806 and 5011 were associated with low (nonpersistent-NP) and high (persistent-P) adaptation to the MG, respectively. Strain 5011 (P), agr group I, cap8 positive and strong biofilm producer showed higher capacity to adhere/internalize in MAC-T compared with strain 806 (NP), characterized as agr group II, cap5 positive and weak biofilm producer. Strain 5011(P) could be recovered from MAC-T lysates up to 72 h pi; while strain 806 (NP) could be recovered only at 4 h pi. Strain 5011 (P) showed greater capacity to induce apoptosis compared with strain 806 (NP) at 4, 24 and 48 h pi. Macrophages infected with strain 5011 (P) showed a greater phagocytic capacity and higher percentage of intracellular reactive oxygen species (ROS) production than strain 806 (NP). No viable bacteria were isolated from macrophages lysates stimulated with any of the S. aureus strains at 2, 4, 8 and 24 h pi. The knowledge of the molecular profile of the S. aureus strains causing bovine mastitis in a herd could become a tool to expose the most prevalent virulence gene patterns and advance in the elucidation of the pathogenesis of chronic mastitis.

Clostridium sordellii-associated gas gangrene in 8 horses, 1998-2019.

Gas gangrene occurs in several animal species and is caused by one or more clostridial species. In horses, the disease is most often caused by Clostridium perfringens type A. Although Clostridium sordellii has been associated with gas gangrene in ruminants and humans, cases of the disease associated with this microorganism have not been described in horses, to our knowledge. We report herein 8 cases of gas gangrene caused by C. sordellii in horses. These cases were characterized by myonecrosis and cellulitis, associated with systemic changes suggestive of toxic shock. The diagnosis was confirmed by gross and microscopic changes combined with anaerobic culture, fluorescent antibody test, immunohistochemistry, and/or PCR. The predisposing factor in these cases was an injection or a traumatic skin injury. C. sordellii should be considered as a possible etiologic agent in cases of gas gangrene in horses.

Characterization of immune response in Staphylococcus aureus chronically infected bovine mammary glands during active involution.

The aim of this study was to characterize the immune response in Staphylococcus aureus chronically infected bovine mammary glands during active involution. Twenty-one Holstein non-pregnant cows in late lactation either uninfected or with chronic naturally acquired S. aureus intramammary infections (IMI) were included in this study. Cows were slaughtered at 7, 14 and 21 d after cessation of milking and samples for immunohistochemical analysis were taken. Protein expression of toll-like receptor 2 (TLR2) and TLR4 was significantly higher in S. aureus-infected quarters than in uninfected controls at the three involution stages studied. Protein expression of tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1α and IL-17 was significantly affected by IMI; being higher in S. aureus-infected than uninfected quarters during all evaluated stages. In S. aureus-infected and uninfected quarters protein expression of lactoferrin increased from day 7-14 of involution, decreasing significantly to day 21 in mammary quarters with chronic infections. The number of monocytes-macrophages was significantly higher in S. aureus-infected than in uninfected control quarters at 7 and 21 d of involution. The number of T lymphocytes was significantly higher in S. aureus-infected than in uninfected quarters at 7 and 14 d of involution while the number of B lymphocytes was significantly higher in S. aureus-infected than in uninfected quarters during all evaluated stages, showing a progressive increase as involution advanced. These results demonstrated a sustained and exacerbated innate and adaptive immune response during chronic S. aureus IMI, playing a critical role in the infection control during active involution.

Immune response of Staphylococcus aureus strains in a mouse mastitis model is linked to adaptive capacity and genotypic profiles.

Staphylococcus aureus is one of the most frequently isolated major pathogens from intramammary infections (IMI) worldwide. The mechanisms by which S. aureus IMI are established and maintained in dairy cows involve both bacterial escape strategies and modulation of the host immune response. Moreover, it was shown that different S. aureus strains have varying effects on the immune response. The aim of this study was to investigate the immune response in a mouse mastitis model of two S. aureus strains isolated from bovine IMI with different clinical manifestation (persistent-P or non-persistent-NP), phenotypic and genotypic profile. Both strains were capable of establishing an IMI after 264h post inoculation (pi). Strain A (NP) showed a more aggressive behaviour than strain B (P) at early stages of IMI, while strain B multiplied initially at a lower rate but increased its replication capacity from 120h pi to the end of the study (264h pi). Strain A triggered a stronger initial inflammatory response compared with strain B inducing higher gene and protein expression of TLR2, NF-κB activation and higher gene expression of IL-1α at initial stage of IMI (6-12h pi) but inducing extensive mammary tissue damage. Immune cells response was different for each S. aureus strain throughout the course of infection, showing mammary glands inoculated with strain A greater initial immune cells stimulation compared with strain B and then a second immune cells stimulation (from 120 to 264h pi) represented by monocytes-macrophages, T and B lymphocytes, mainly stimulated by strain B, consistent with inflammatory process becoming chronic. Strain-specific pathogenicity observed underscores the importance of pathogen factors in the progression of the infectious process. These results contribute to increase the available information on host-pathogen interaction and point out for the need of further research to expand the knowledge about these interactions for developing new strategies to intervene in the IMI progress.

Proliferation-apoptosis balance in Staphylococcus aureus chronically infected bovine mammary glands during involution.

The objective of this study was to determine whether Staphylococcus aureus chronic intramammary infection (IMI) influences expression of proteins related to regulation of proliferation and apoptosis processes and proliferation/apoptosis index during active involution in bovine mammary gland. Twenty-one Holstein non-pregnant cows in late lactation either uninfected or with chronic naturally acquired S. aureus IMI were included in this study. Cows were slaughtered at 7, 14 and 21 d after cessation of milking and samples for immunohistochemical analysis were taken. Protein expression of Bcl-2, Bax, Fas and active caspase-3 in mammary tissue was significantly affected by chronic S. aureus IMI, all showing increased immunoexpression in S. aureus-infected quarters at all involution stages. The percentage of apoptotic cells was increased by IMI in both mammary parenchyma and stroma, and the percentage of parenchymal and stromal cell proliferation was also increased. The proliferation/apoptosis ratio was significantly increased by IMI only in stromal cells. This imbalance to favour proliferation in S. aureus-infected mammary quarters could be one of the underlying causes that induce aberrant involution with permanence of nonsecretory tissue and increase of stromal components.