Emulsion-Based Postbiotic Formulation Is Comparable to Viable Cells in Eliciting a Localized Immune Response in Dairy Cows With Chronic Mastitis

Biomolecule-Producing Probiotic Bacterium Lactococcus lactis in Free or Nanoencapsulated Form for Endometritis Treatment and Fertility Improvement in Buffaloes

A Lactococcus (L.) lactis strain producing antimicrobial and anti-inflammatory biomolecules (mainly 1,4-Diaza-2,5-dioxobicyclo[4.3.0]nonanes and pyrazine-derivatives) was tested for its capacity to cure clinical endometritis in buffaloes compared to conventional antibiotic-based treatment. Clinical endometritis-diagnosed buffaloes (n = 16/group) were infused intrauterine with four doses of 109 CFU-free (FLC group) or nanoencapsulated L. lactis (NLC group) and compared to those that received three doses of saline + a single dose of 500 mg cephapirin benzathin (AB group) or four doses of saline (control, C group) every other day. Endometrium samples were analyzed for cytological (polymorphonuclear cells, PMN), bacteriological, and proinflammatory mRNA expression. Uterine wash and blood samples were collected to determine proinflammatory cytokine concentrations and metabolites in the blood samples. The reproductive performance of buffaloes was assessed. Compared to the C group, the AB and NLC groups had the lowest percentage of PMN, followed by those in the FLC group (p < 0.05). All treated buffaloes had significantly lower numbers of pathogens than the control buffaloes. Compared to control, all treatments significantly down-regulated endometrial proinflammatory encoding mRNA expression. The concentrations of IL1B, TNFAIP7, and leukocyte esterase activity in the uterine washings were significantly decreased in the AB and NLC groups compared to the C and FLC groups. All treatments significantly decreased concentrations of serum proinflammatory cytokines compared to control. Both the AB and NLC groups had significantly lower concentrations of serum NEFA than the C and FLC groups. The percentage of control buffaloes having an echogenic uterus and PVD score > 2 was significantly higher than those in the treated buffaloes with higher numbers of corpora lutea, higher conception rates, and shorter days open than control buffaloes (p < 0.05). In conclusion, L. lactis-producing antimicrobial and anti-inflammatory metabolites reduce uterine inflammatory responses and improve fertility in buffaloes.

Beyond probiotics: Exploring the potential of postbiotics and parabiotics in veterinary medicine

Postbiotics and parabiotics (PP) are emerging fields of study in animal nutrition, preventive veterinary medicine, and animal production. Postbiotics are bioactive compounds produced by beneficial microorganisms during the fermentation of a substrate, while parabiotics are inactivated beneficial microbial cells, either intact or broken. Unlike probiotics, which are live microorganisms, PP are produced from a fermentation process without live cells and show significant advantages in promoting animal health owing to their distinctive stability, safety, and functional diversity. PP have numerous beneficial effects on animal health, such as enhancing growth performance, improving the immune system and microbiota of the gastrointestinal tract, aiding ulcer healing, and preventing pathogenic microorganisms from colonizing in the skin. Moreover, PP have been identified as a potential alternative to traditional antibiotics in veterinary medicine due to their ability to improve animal health without the risk of antimicrobial resistance. This review comprehensively explores the current research and applications of PP in veterinary medicine. We aimed to thoroughly examine the mechanisms of action, benefits, and potential applications of PP in various species, emphasizing their use specifically in livestock and poultry. Additionally, we discuss the various routes of administration to animals, including feed, drinking water, and topical use. This review also presents in-depth information on the methodology behind the preparation of PP, outlining the criteria employed to select appropriate microorganisms, and highlighting the challenges commonly associated with PP utilization in veterinary medicine.

Fighting antibiotic resistance in the local management of bovine mastitis

Bovine mastitis is a widespread infectious disease with a significant economic burden, accounting for 80 % of the antibiotic usage in dairy animals. In recent years, extensive research has focused on using biomimetic approaches such as probiotics, bacteriocins, bacteriophages, or phytochemicals as potential alternatives to antibiotics. The local administration of therapeutic molecules through the intramammary route is one of the most commonly strategies to manage bovine mastitis. This review highlights the most important findings in this field and discusses their local application in mastitis therapy. In contrast to antibiotics, the proposed alternatives are not limited to promote bacterial death but consider other factors associated to the host microenvironments. To this end, the proposed biomimetic strategies can modulate different stages of infection by modifying the local microbiota, preventing oxidative stress, reducing bacterial adhesion to epithelial cells, modulating the immune response, or mediating the inflammatory process. Numerous in vitro studies support the antimicrobial, antibiofilm or antioxidant properties of these alternatives. However, in vivo studies incorporating these components within pharmaceutical formulations with potential clinical application are limited. The development of secure, stable, and effective drug delivery systems based on the proposed options is necessary to achieve real alternatives to antibiotics in the clinic.

Development of innate immune memory by non-immune cells during Staphylococcus aureus infection depends on reactive oxygen species

Introduction

The mechanisms underlying innate immune memory (trained immunity) comprise epigenetic reprogramming of transcriptional pathways associated with alterations of intracellular metabolism. While the mechanisms of innate immune memory carried out by immune cells are well characterized, such processes in non-immune cells, are poorly understood. The opportunistic pathogen, Staphylococcus aureus, is responsible for a multitude of human diseases, including pneumonia, endocarditis and osteomyelitis, as well as animal infections, including chronic cattle mastitis that are extremely difficult to treat. An induction of innate immune memory may be considered as a therapeutic alternative to fight S. aureus infection.

Methods

In the current work, we demonstrated the development of innate immune memory in non-immune cells during S. aureus infection employing a combination of techniques including Enzyme-linked immunosorbent assay (ELISA), microscopic analysis, and cytometry.

Results

We observed that training of human osteoblast-like MG-63 cells and lung epithelial A549 cells with β-glucan increased IL-6 and IL-8 production upon a stimulation with S. aureus, concomitant with histones modifications. IL-6 and IL-8 production was positively correlated with an acetylation of histone 3 at lysine 27 (H3K27), thus suggesting epigenetic reprogramming in these cells. An addition of the ROS scavenger N-Acetylcysteine, NAC, prior to β-glucan pretreatment followed by an exposure to S. aureus, resulted in decreased IL-6 and IL-8 production, thereby supporting the involvement of ROS in the induction of innate immune memory. Exposure of cells to Lactococcus lactis resulted in increased IL-6 and IL-8 production by MG-63 and A549 cells upon a stimulation with S. aureus that was correlated with H3K27 acetylation, suggesting the ability of this beneficial bacterium to induce innate immune memory.

Discussion

This work improves our understanding of innate immune memory in non-immune cells in the context of S. aureus infection. In addition to known inducers, probiotics may represent good candidates for the induction of innate immune memory. Our findings may help the development of alternative therapeutic approaches for the prevention of S. aureus infection.