Infective mastitis due to bovine‐associated Streptococcus dysgalactiae contributes to clinical persistent presentation in a murine mastitis model

Abstract

Background Mastitis caused by Streptococcus dysgalactiae (GCS) is a major pathology of dairy cows. The mechanisms by which GCS intramammary infection is established and maintained involve not only bacterial adherence and invasion but also modulation of the cytokines and TLR immune response. Objectives The study aimed to evaluate characteristics of persistent infection of GCS collected from bovine mastitis milk in a murine mastitis model whose mammary structure is similar to that of dairy cows; dairy cow mastitis can be well simulated by using mice as models. HLJ2019 was tested for its ability to persistently infected mice by intramammary inoculation. Methods As antibiotics tested, establish an intramammary infection model in murine, histopathology analyses, relative expression of inflammatory cytokines mRNA and adherence and invasion in mMECs. Results It induced a robust inflammatory reaction in the mammary gland, characterized by histopathological changes, increased myeloperoxidase activity and induced expression of inflammatory cytokines (TNF‐α, IL‐6, IFN‐γ, IL‐10, IL‐1α and IL‐1β) and TLR2/4, the exhibited strong LDH release, adhesion and invasive abilities in contact with mMECs. Conclusion These results contribute to increase the available information on host‐pathogen interaction and point out the need for further research to expand the knowledge about these interactions for developing new strategies to intervene in the intramammary persistent infection progress.

Mammary epithelial cell-derived exosomal miR-155-inhibitor played a key role in the treatment of mastitis via down-regulation of TLRs/NF-κB signaling pathway to inhibit inflammatory response

“…However, the alterations in the expression of the above genes were significantly recovered by adding miR-155 inhibitor-loaded exosomes, which indicated that miR-155 might alleviate mastitis via the TLRs/NF-κB signaling pathway. The previous study has shown that the levels of TNF-α, IL-1β, and IL-10 were increased in Mastitis induced by LPS (37). We also found the same changes in the levels of TNF-α, IL-1β, and IL-10 in LPS-induced HC11 cells in our study.…”

Subcutaneous Streptococcus dysgalactiae GAPDH vaccine in mice induces a proficient innate immune response

“…In the present study, HLJ2019 was used to confirm the protective effect and demonstrate the positive benefits of rGAPDH in the lethal infection model. Previous research from the authors’ laboratory showed that HLJ2019 produces chronic infection symptoms in the mammary gland of the mice [ 30 ]. Recombinant GAPDH adjuvanted with Freund's adjuvant was synthesized and injected subcutaneously into mice.…”

Evaluation of Streptococcus species isolated from subclinical sheep mastitis by molecular methods and determination of virulence factors and antimicrobial resistance genes

“…Among microorganisms responsible for sheep mastitis, streptococci rank second in importance after staphylococci (Kumar et al 2013). Both S. uberis and S. agalactiae can induce chronic mastitis in cows (An et al 2021). Although, S. uberis is primarily an environmental pathogen, cases of transmission have been observed.…”