Causes, types, etiological agents, prevalence, diagnosis, treatment, prevention, effects on human health and future aspects of bovine mastitis

Genetic basis of antibiotic resistance in bovine mastitis and its possible implications for human and ecological health

Bovine mastitis is a mammary gland inflammation that can occur due to infectious pathogens, Staphylococcus aureus and Escherichia coli, which are, respectively, the most prevalent Gram-positive and Gram-negative bacteria associated with this disease. Currently, antibiotic treatment has become more complicated due to the presence of resistant pathogens. This review, therefore, aims to identify the most common resistance genes reported for these strains in the last four years. During the review, it was noted that blaZ, blaSHV, blaTEM, and blaampC are the most reported genes for S. aureus and E. coli, associated with drug inactivation, mainly β-lactamases. They are characterized by generating bacterial resistance to β-lactam antibiotics, the most common treatment in animal and human bacterial treatments (penicillins and cephalosporins, among others). Genes associated with efflux systems were also present in the two strains and included norA, tetA, tetC, and tetK, which generate resistance to macrolide and tetracycline antibiotics. Additionally, the effects of spreading resistance between animals and humans through direct contact (such as consumption of contaminated milk) or indirect contact (through environmental contamination) has been deeply discussed, emphasizing the importance of having adequate sanitation and antibiotic control and administration protocols.

Development potential of selenium in the prevention and treatment of bovine endometritis

Endometritis is a common postpartum disease in cows. It delays uterine involution and impairs normal physiological function. This can result in long-term or even lifelong infertility and cause significant losses to the dairy farming industry. Traditional treatments like antibiotics possess certain shortcomings, such as antibiotic residues, the abuse of antibiotics, and increased antimicrobial resistance of pathogens. Alternative treatment strategies are needed to minimize the utilization of antibiotics in dairy production. As an essential trace element in animals, selenium (Se) plays a vital role in regulating immune function, the inflammatory response, and oxidative stress, affecting the speed and completeness of tissue repair. This paper reviewed previous studies to analyse the potential of Se in the prevention and treatment of bovine endometritis, aiming to provide a new direction to increase production capacity in the future.

Regulation of Inflammatory Responses of Cow Mammary Epithelial Cells through MAPK Signaling Pathways of IL-17A Cytokines

The aim of this study is to explore the mechanism of IL-17A infection in the development of bacterial mastitis in dairy cows. In this study, RT-qPCR and ELISA were used to measure the promoting effect of IL-17A on the generation of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and chemokine (IL-8). In addition, Western blot (WB) was applied to measure the influences of IL-17A on the inflammation-related ERK and p38 proteins in the MAPK pathways. The results show that under the stimulation of LPS on cow mammary epithelial cells (CMECs), cytokines IL-1β, IL-6, IL-8, TNF-α, and IL-17A will exhibit significantly increased expression levels (p < 0.05). With inhibited endogenous expression of IL-17A, cytokines IL-1β, IL-6, IL-8, and TNF-α will present reduced genetic expression (p < 0.01), with reduced phosphorylation levels of ERK and p38 proteins in the MAPK signaling pathways (p < 0.001). Upon the exogenous addition of the IL-17A cytokine, the genetic expression of cytokines IL-1β, IL-6, IL-8, and TNF-α will increase (p < 0.05), with increased phosphorylation levels of the ERK and p38 proteins in the MAPK signaling pathways (p < 0.001). These results indicate that under the stimulation of CMECs with LPS, IL-17A can be expressed together with relevant inflammatory cytokines. Meanwhile, the inflammatory responses of mammary epithelial cells are directly proportional to the expression levels of IL-17A inhibited alone or exogenously added. In summary, this study shows that IL-17A could be used as an important indicator for assessing the bacterial infections of mammary glands, indicating that IL-17A could be regarded as one potential therapeutic target for mastitis.

Selenomethionine Inhibits NF-κB-mediated Inflammatory Responses of Bovine Mammary Epithelial Cells Caused by Klebsiella pneumoniae by Increasing Autophagic Flux

Klebsiella pneumoniae (K. pneumoniae) is one of the major pathogens causing bovine clinical mastitis. Autophagy maintains cellular homeostasis and resists excessive inflammation in eukaryotic organisms. Selenomethionine (Se-Met) is commonly used as a source of selenium supplementation for dairy cows. This study aimed to investigate the effects of Se-Met on inflammatory responses mediated by nuclear factor-kappa B (NF-κB) through autophagy. We infected bovine mammary epithelial cell line (MAC-T) with K. pneumoniae and examined the expression of autophagy-related proteins and changes in autophagic vesicles, LC3 puncta, and autophagic flux at various intervals. The results showed that K. pneumoniae activated the early-stage autophagy of MAC-T cells. The levels of LC3-II, Beclin1, and ATG5, as well as the number of LC3 puncta and autophagic vesicles, increased after 2 h post-treatment. However, the late-stage autophagic flux was blocked. Furthermore, the effect of autophagy on NF-κB-mediated inflammation was investigated with different autophagy levels. The findings showed that enhanced autophagy inhibited the K. pneumoniae-induced inflammatory responses of MAC-T cells. The opposite results were found with the inhibition of autophagy. Finally, we examined the effect of Se-Met on NF-κB-mediated inflammation based on autophagy. The results indicated that Se-Met alleviated K. pneumoniae-induced autophagic flux blockage, inhibited NF-κB-mediated inflammation, and decreased the adhesion of K. pneumoniae to MAC-T cells. The inhibitory effect of Se-Met on NF-κB-mediated inflammation could be partially blocked by the autophagy inhibitor chloroquine (CQ). Overall, Se-Met attenuated K. pneumoniae-induced NF-κB-mediated inflammatory responses by enhancing autophagic flux.

Forsythiaside A attenuates mastitis via PINK1/Parkin-mediated mitophagy

BACKGROUND

Bovine mastitis is the most common animal production disease in the global dairy industry, which affects the health of dairy cows. When bovine mastitis occurs, the mitochondrial metabolism of breast tissue increases, and the relationship between inflammation and mitophagy has become a hot topic for many scholars. The abuse of antibiotics leads to the increase of resistance to bovine mastitis. FTA is one of the main effective components of Forsythia suspensa, which has anti-inflammatory, anti-infection, anti-oxidation and anti-virus pharmacological effects, and has broad application prospects in the prevention and treatment of bovine mastitis. However, the relationship between the anti-inflammatory effects of FTA and mitophagy is still unclear.

PURPOSE

This study mainly explores the anti-inflammatory effect of FTA in bovine mastitis and the relationship between mitophagy.

METHODS

MAC-T cells and wild-type mice were used to simulate the in vitro and in vivo response of mastitis. After the pretreatment with FTA, CsA inhibitors and siPINK1 were used to interfere with mitophagy, and the mitochondrial function impairment and the expression of inflammatory factors were detected.

RESULTS

It was found that pre-treatment with FTA significantly reduced LPS induced inflammatory response and mitochondrial damage, while promoting the expression of mitophagy related factors. However, after inhibiting mitophagy, the anti-inflammatory effect of FTA was inhibited.

CONCLUSION

This study is the first to suggest the relationship between the anti-inflammatory effect of FTA and mitophagy. PINK1/Parkin-mediated mitophagy is one of the ways that FTA protects MAC-T cells from LPS-induced inflammatory damage.

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.

Preparation and Antimicrobial Activity of a Film-Forming Polyhexamethylene Biguanide Teat Disinfectant

Bovine mastitis caused by infectious pathogens can lead to a decline in production performance and an increase in elimination rate, resulting in huge losses to the dairy industry. This study aims to prepare a novel dairy cow teat disinfectant with polyhexamethylene biguanide (PHMB) as the main bactericidal component and to evaluate its bactericidal activity in vitro and its disinfection effect in dairy cow teats. PHMB disinfectant with a concentration of 3 g/L was prepared with PVA-1788, propylene glycol and glycerol as excipients. When the dilution ratio is 1:4800 and the action time is 5 min, the PHMB teat disinfectant can reduce the four types of bacteria (S. agalactiae ATCC 12386, S. dysgalactiae ATCC 35666, S. aureus ATCC 6538, and E. coli ATCC 8099) by 99.99%. PHMB teat disinfectant applied on the skin of rabbits with four bacteria types achieved an average log10 reduction greater than 4. After 30 s of PHMB teat disinfectant dipping, the bacteria of cow teats were counted prior to disinfection. The mean log10 reduction in bacteria on the skin surface of 12 cows ranged from 0.99 to 3.52 after applying the PHMB teat disinfectant for 10 min. After 12 h, the PHMB teat disinfectant achieved an average log10 reduction in bacteria from 0.27 to 0.68 (compared with that prior to disinfection). These results suggested that PHMB teat disinfection has the potential to prevent and treat mastitis-causing bacteria in dairy herds.

Potential of phage EF-N13 as an alternative treatment strategy for mastitis infections caused by multidrug-resistant Enterococcus faecalis

Bovine mastitis is the most common and costly disease affecting dairy cattle throughout the world. Enterococcus faecalis is one of the environmental origin mastitis-causing pathogens. The treatment of bovine mastitis is primarily based on antibiotics. Due to the negative impact of developing antibiotic resistance and adverse effects on soil and water environments, the trend toward use of nonantibiotic treatments is increasing. Phages may represent a promising alternative treatment strategy. However, it is unknown whether phages have therapeutic effects on E. faecalis-induced mastitis. Thus, the objective of this study was to investigate the degree of protection conferred by a phage during murine mastitis caused by multidrug-resistant E. faecalis. Enterococcus faecalis was isolated from the milk of dairy cows with mastitis, and a phage was isolated using the E. faecalis isolates as hosts. The bactericidal ability of the phage against E. faecalis and the ability to prevent biofilm formation were determined in vitro. The therapeutic potential of the phage on murine mastitis was evaluated in vivo. We isolated 14 strains of E. faecalis from the milk of cows with mastitis, all of which exhibited multidrug resistance, and most (10/14) could form strong biofilms. Subsequently, a new phage (EF-N13) was isolated using the multidrug-resistant E. faecalis N13 (isolated from mastitic milk) as the host. The phage EF-N13 belongs to the family Myoviridae, which has short latent periods (5 min) and high bursts (284 pfu/cell). The genome of EF-N13 lacked bacterial virulence-, antibiotic resistance-, and lysogenesis-related genes. Furthermore, bacterial loading in the raw milk medium was significantly reduced by EF-N13 and was unaffected by potential IgG antibodies. In fact, EF-N13 could effectively prevent the formation of biofilm by multidrug-resistant E. faecalis. All of these characteristics suggest that EF-N13 has potential as mastitis therapy. In vivo, 1 × 105 cfu/gland of multidrug-resistant E. faecalis N13 resulted in mastitis development within 24 h. A single dose of phage EF-N13 (1 × 104, 1 × 105, or 1 × 106 pfu/gland) could significantly decrease bacterial counts in the mammary gland at 24 h postinfection. Histopathological observations demonstrated that treatment with phage EF-N13 effectively alleviated mammary gland inflammation and damage. This effect was confirmed by the lower levels of proinflammatory cytokines IL-6, IL-1β, and tumor necrosis factor-α in the mammary gland treated with phage EF-N13 compared with those treated with phosphate-buffered saline. Overall, the data underscored the potential of phage EF-N13 as an alternative therapy for bovine mastitis caused by multidrug-resistant E. faecalis.

ALKBH5 Stabilized N6-Methyladenosine-Modified LOC4191 to Suppress E. coli-Induced Apoptosis

E. coli is a ubiquitous pathogen that is responsible for over one million fatalities worldwide on an annual basis. In animals, E. coli can cause a variety of diseases, including mastitis in dairy cattle, which represents a potential public health hazard. However, the pathophysiology of E. coli remains unclear. We found that E. coli could induce global upregulation of m6A methylation and cause serious apoptosis in bovine mammary epithelial cells (MAC-T cells). Furthermore, numerous m6A-modified lncRNAs were identified through MeRIP-seq. Interestingly, we found that the expression of LOC4191 with hypomethylation increased in MAC-T cells upon E. coli-induced apoptosis. Knocking down LOC4191 promoted E. coli-induced apoptosis and ROS levels through the caspase 3-PARP pathway. Meanwhile, knocking down ALKBH5 resulted in the promotion of apoptosis through upregulated ROS and arrested the cell cycle in MAC-T cells. ALKBH5 silencing accelerated LOC4191 decay by upregulating its m6A modification level, and the process was recognized by hnRNP A1. Therefore, this indicates that ALKBH5 stabilizes m6A-modified LOC4191 to suppress E. coli-induced apoptosis. This report discusses an initial investigation into the mechanism of m6A-modified lncRNA in cells under E. coli-induced apoptosis and provides novel insights into infectious diseases.

Saikosaponin A alleviates Staphylococcus aureus-induced mastitis in mice by inhibiting ferroptosis via SIRT1/Nrf2 pathway

Mastitis is a common and serious bacterial infection of the mammary gland. Saikosaponin A (SSA) is a triterpenoid saponin isolated from Bupleurum falcatum that has the ability to treat various diseases. However, little is known about the role of SSA in achieving mastitis remission. Here, we found that SSA alleviated Staphylococcus aureus (S. aureus)-induced mastitis by attenuating inflammation and maintaining blood-milk barrier integrity. Furthermore, S. aureus activated nuclear factor kappa B (NF-κB) pathway by upregulated p-p65 and p-IκB. S. aureus also induced ferroptosis in mammary gland in mice, mainly characterized by excessive iron accumulation, mitochondrial morphological changes and impaired antioxidant production. However, S. aureus-induced NF-κB activation and ferroptosis were prevented by SSA. Moreover, SAA could upregulate the expression of SIRT1, Nrf2, HO-1 and GPX4. And the inhibitory effects of SAA on inflammation and ferroptosis were reversed by SIRT1 inhibitor EX-527. In conclusion, SAA protected S. aureus-induced mastitis through suppressing inflammation and ferroptosis by activating SIRT1/Nrf2 pathway.

Effect of feeding dairy calves with milk fermented with selected probiotic strains on occurrence of diarrhoea, carriage of pathogenic and zoonotic microorganisms and growth performance

Calf-diarrhoea is a major health problem in dairy calves and a primary reason for use of antimicrobials. We aimed to investigate the effect of feeding milk fermented with a combination of four probiotic bacterial strains to young-calves on; occurrence of diarrhoea and associated-pathogens (bacteria, virus and parasites), shedding of Salmonella Dublin and Campylobacter, occurrence of virulence genes linked to Clostridium perfringens, Enterotoxigenic Escherichia coli and shiga-toxin producing E. coli (STEC), as well as growth performance. For this, 143 new-born calves from three Danish dairy-farms were allocated into Treatment- (fed the fermented milk for the first 8-weeks-of-life) and Control-groups (fed regular farm-milk). Diarrhoea was observed in 18.6 % (Farm 1), 22.4 % (Farm 2) and 15.7 % (Farm 3) of the total registrations mainly within the first 3-weeks-of-life. C. perfringens was the most frequently detected pathogen. The treatment did not affect the occurrence of virulence genes linked to STEC and C. perfringens and, overall, their detection levels were very low/undetected. The statistical model applied found no significant effect of the treatment on prevalence of early-diarrhoea (≤ 3 weeks), late-diarrhoea (>3 weeks), occurrence of C. perfringens and Cryptosporidium parvum or levels of Campylobacter spp. Limited detection of the other pathogens and associated virulence-genes under study, did not allow for assessment of the impact of the treatment on their occurrence. Notably, the feeding-approach showed a significant detrimental effect on daily-weight-gain. The inefficacy of the treatment may be associated with the complexity of influencing factors under field conditions including management practices.

Investigation of milk microbiota of healthy and mastitic Sahiwal cattle

BACKGROUND

Sahiwal cattle is an indigenous cattle breed of Pakistan and mastitis is one of the major problems faced by Sahiwal cattle which hinders its production potential. The study was designed to investigate the milk microbiota of healthy and mastitic Sahiwal cattle as part of a multistep project to develop probiotics for the mitigation and control of mastitis. Milk samples of Sahiwal cattle (healthy clinical mastitis and subclinical mastitis) reared under similar husbandry and management practices were processed for 16S rRNA gene base metagenomics analysis.

RESULTS

Results revealed that Proteobacteria were dominant in the healthy group and subclinical mastitis group (56.48% and 48.77%, respectively) as compared to the clinical mastitis group (2.68%). In contrast, Firmicutes were abundant in the clinical mastitis group (64%) as compared to the healthy and subclinical mastitis groups (15.87% and 38.98%, respectively). Dominant species assigned in the healthy group were Ignavibacterium album, Novosphingobium capsulatum, Akkermansia muciniphila and Lactobacillus fermentum.The clinical mastitis group was dominated by Streptococcus dysgalactiae and Corynebacterium bovis, while subclinical mastitis group included Lactobacillus fermentum and uncultured acidobacteriales and Akkermansia muciniphila as dominant species. Alpha diversity indices showed higher microbial diversity in the healthy group compared to the clinical and sub-clinical mastitis groups.

CONCLUSION

It is concluded that the milk microbiota of healthy sahiwal cattle has higher diversity and dominant taxa in the different groups may be used as signature microbes for mastitis susceptibility. Akkermansia muciniphila is one of candidate specie that was identified and may be used for development of probiotics.

Coexpression analysis of lncRNAs and mRNAs identifies potential regulatory long noncoding RNAs involved in the inflammatory effects of lipopolysaccharide on bovine mammary epithelial cells

BACKGROUND

The infection of bovine mammary glands by pathogenic microorganisms not only causes animal distress but also greatly limits the development of the dairy industry and animal husbandry. A deeper understanding of the host's initial response to infection may increase the accuracy of selecting drug-resistant animals or facilitate the development of new preventive or therapeutic intervention strategies. In addition to their functions of milk synthesis and secretion, bovine mammary epithelial cells (BMECs) play an irreplaceable role in the innate immune response. To better understand this process, the current study identified differentially expressed long noncoding lncRNAs (DE lncRNAs) and mRNAs (DE mRNAs) in BMECs exposed to Escherichia coli lipopolysaccharide (LPS) and further explored the functions and interactions of these lncRNAs and mRNAs.

RESULTS

In this study, transcriptome analysis was performed by RNA sequencing (RNA-seq), and the functions of the DE mRNAs and DE lncRNAs were predicted by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Next, we constructed a modulation network to gain a deeper understanding of the interactions and roles of these lncRNAs and mRNAs in the context of LPS-induced inflammation. A total of 231 DE lncRNAs and 892 DE mRNAs were identified. Functional enrichment analysis revealed that pathways related to inflammation and the immune response were markedly enriched in the DE genes. In addition, research results have shown that cell death mechanisms, such as necroptosis and pyroptosis, may play key roles in LPS-induced inflammation.

CONCLUSIONS

In summary, the current study identified DE lncRNAs and mRNAs and predicted the signaling pathways and biological processes involved in the inflammatory response of BMECs that might become candidate therapeutic and prognostic targets for mastitis. This study also revealed several possible pathogenic mechanisms of mastitis.

Exploring the distinct immunological reactions of bovine neutrophils towards major and minor pathogens responsible for mastitis

Bovine mastitis is primarily caused by a group of bacteria known as Staphylococcus and Streptococcus. However, additional types of bacteria, such as bovine non-aureus staphylococci and mammaliicocci (NASM) as well as lactic acid bacteria (LAB), are considered minor pathogens and have less impact on cows. Modulating bovine neutrophil activities and gene expressions in response to bacterial stimuli prompted the cells to execute effector functions to combat udder infections. Although neutrophils can manage major mastitis-causing bacteria, this strategy has not been tested against minor pathogens, i.e. NASM, Weissella spp. Our main objective was to investigate how neutrophils interacted with major and minor pathogens during in vitro bacterial stimulation. The results reveal that neutrophils performed offensive duties regardless of the type of bacteria encountered. Neutrophils generated high levels of reactive oxygen species, efficiently phagocytosed both types of bacteria, and facilitated extracellular killing by releasing NET structures against all bacteria. In addition, neutrophils migrated preferentially towards the majors rather than the minors, although myeloperoxidase (MPO) degranulation did not differ substantially across bacteria. Furthermore, the killing capacity of neutrophils was not dependent on any particular bacterium. The correlation of effector functions is intimately linked to the up-regulation of genes associated with the above functions, except for IL6, which was down-regulated. Furthermore, neutrophil apoptosis can be modulated by altering apoptosis-associated genes in response to harmful stimuli. These findings provide valuable information on how neutrophils react to major and minor mastitis-causing bacteria. However, future research should explore the interplay between minor pathogens and the host's responses.

Bovine mastitis, a worldwide impact disease: Prevalence, antimicrobial resistance, and viable alternative approaches

Bovine mastitis is globally considered one of the most important diseases within dairy herds, mainly due to the associated economic losses. The most prevalent etiology are bacteria, classified into contagious and environmental, with Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, Escherichia coli and Klebsiella pneumoniae being the most common pathogens associated with mastitis cases. To date these pathogens are resistant to the most common active ingredients used for mastitis treatment. According to recent studies resistance to new antimicrobials has increased, which is why developing of alternative treatments is imperative. Therefore the present review aims to summarize the reports about bovine mastitis along 10 years, emphasizing bacterial etiology, its epidemiology, and the current situation of antimicrobial resistance, as well as the development of alternative treatments for this pathology. Analyzed data showed that the prevalence of major pathogens associated with bovine mastitis varied according to geographical region. Moreover, these pathogens are classified as multidrug-resistant, since the effectiveness of antimicrobials on them has decreased. To date, several studies have focused on the research of alternative treatments, among them vegetal extracts, essential oils, or peptides. Some other works have reported the application of nanotechnology and polymers against bacteria associated with bovine mastitis. Results demonstrated that these alternatives may be effective on bacteria associated with bovine mastitis.

Exploring the Milk Microbiota of Healthy and Mastitic Nili Ravi Buffalo Using 16S rRNA Gene Base Metagenomic Analysis

The Nili Ravi, a buffalo breed from Pakistan, significantly contributes to the dairy industry. Mastitis is one of the major challenges affecting milk production in this breed. The objective of the current study was to identify the bacterial communities and diversity in healthy and mastitic milk of this breed. Milk samples (n = 14) were collected from Nili Ravi buffaloes with different udder health statuses, i.e., healthy (5), subclinical mastitis (4), and clinical mastitis (5). The DNAs were extracted, subjected to partial amplification of 16S rDNA (V3 and V4 regions), and sequenced using the Illumina platform. The results revealed variations in the bacterial communities in the milk of animals with different udder health statuses. Proteobacteria was the predominant phylum in the healthy group, while clinical and subclinical mastitis milk had a higher abundance of Firmicutes. Dominant bacterial genera in the healthy group were Streptococcus (11.60%), Herbaspirillum (7.65%), and Staphylococcus (4.70%), whereas the clinical mastitis group was dominated by Streptococcus (33.96%), Staphylococcus (7.87%), and Corynebacterium (2.68%), and the subclinical mastitis group was dominated by Bacillus (15.70%), Corynebacterium (6.70%), and Staphylococcus (6.58%). Assignment of operational taxonomic units at the species level resulted in most species being assigned to uncultured or unknown bacteria or remaining unassigned. Alpha diversity indices indicated lower microbial diversity in the clinical mastitis group, while beta diversity indices showed a scattered pattern of sample clustering in PCA plots among different groups. It is concluded that bacterial diversity in the milk of Nili Ravi buffaloes suffering from clinical mastitis is lower compared to healthy and subclinical mastitis cases. It is concluded that the variations in the microbiota of healthy and mastitic milk may be further investigated and exploited as signature microbes associated with the udder health status of Nili Ravi buffalo.

Advances in Diagnostic Approaches and Therapeutic Management in Bovine Mastitis

Mastitis causes huge economic losses to dairy farmers worldwide, which largely negatively affects the quality and quantity of milk. Mastitis decreases overall milk production, degrades milk quality, increases milk losses because of milk being discarded, and increases overall production costs due to higher treatment and labour costs and premature culling. This review article discusses mastitis with respect to its clinical epidemiology, the pathogens involved, economic losses, and basic and advanced diagnostic tools that have been used in recent times to diagnose mastitis effectively. There is an increasing focus on the application of novel therapeutic approaches as an alternative to conventional antibiotic therapy because of the decreasing effectiveness of antibiotics, emergence of antibiotic-resistant bacteria, issue of antibiotic residues in the food chain, food safety issues, and environmental impacts. This article also discussed nanoparticles'/chitosan's roles in antibiotic-resistant strains and ethno-veterinary practices for mastitis treatment in dairy cattle.

Punch-excised explants of bovine mammary gland to model early immune response to infection

BACKGROUND

Mammary gland (MG) infections (mastitis) are frequent diseases of dairy cows that affect milk quality, animal welfare and farming profitability. These infections are commonly associated with the bacteria Escherichia coli and Staphylococcus aureus. Different in vitro models have been used to investigate the early response of the MG to bacteria, but the role of the teat in mastitis pathogenesis has received less attention. In this study, we used punch-excised teat tissue as an ex vivo model to study the immune mechanisms that arise early during infection when bacteria have entered the MG.

RESULTS

Cytotoxicity and microscopic analyses showed that bovine teat sinus explants have their morphology and viability preserved after 24 h of culture and respond to ex vivo stimulation with TLR-agonists and bacteria. LPS and E. coli trigger stronger inflammatory response in teat when compared to LTA and S. aureus, leading to a higher production of IL-6 and IL-8, as well as to an up-regulation of proinflammatory genes. We also demonstrated that our ex vivo model can be applied to frozen-stored explants.

CONCLUSIONS

In compliance with the 3Rs principle (replacement, reduction and refinement) in animal experimentation, ex vivo explant analyses proved to be a simple and affordable approach to study MG immune response to infection. This model, which better reproduces organ complexity than epithelial cell cultures or tissue slices, lends itself particularly well to studying the early phases of the MG immune response to infection.

The Relationship between Reticuloruminal Temperature, Reticuloruminal pH, Cow Activity, and Clinical Mastitis in Dairy Cows

We hypothesized that reticuloruminal temperature, pH as well as cow activity can be used as parameters for the early diagnosis of clinical mastitis in dairy cows. Therefore, we aimed to detect the relationship between these factors and the disease. We randomly selected cows with clinical mastitis and clinically healthy cows (HG) out of 600 milking cows. We recorded the following parameters during the experiment: reticulorumen temperature (RR temp.), reticulorumen pH (RR pH), and cow activity. We used smaXtec boluses (smaXtec animal care technology^®, Graz, Austria). In this investigation, reticulorumen data obtained seven days before diagnosis were compared to HG data from the same time period. CM cows were observed on the same days as the healthy cows. The healthy group's RR pH was 7.32% higher than that of cows with CM. Reticulorumen temperature was also 1.25% higher in the CM group than in the control group. The healthy group had a higher average value for walking activity, which was 17.37% higher than the CM group. The data of reticulorumen pH changes during 24 h showed that during the day, the pH changed from 5.53 to 5.83 in the CM group. By contrast, pH changed from 6.05 to 6.31 in the control group. The lowest reticulorumen pH in the CM group was detected on the third day before diagnosis, which was 15.76% lower than the highest reticulorumen pH detected on the sixth day before diagnosis. The lowest reticulorumen pH in CM cows was detected at 0 and 1 days before diagnosis and it was 1.45% lower than the highest reticulorumen pH detected on the second day before diagnosis. The lowest walking activity in the CM group was detected 0 days before diagnosis, which was 50.60% lower than on the fifth day before diagnosis. Overall, the results confirmed our hypothesis that reticuloruminal temperature, reticuloruminal pH, and cow activity could be used as parameters for the early diagnosis of clinical mastitis in dairy cows.

Alternatives to antibiotics for treatment of mastitis in dairy cows

Mastitis is considered the costliest disease on dairy farms and also adversely affects animal welfare. As treatment (and to a lesser extent prevention) of mastitis rely heavily on antibiotics, there are increasing concerns in veterinary and human medicine regarding development of antimicrobial resistance. Furthermore, with genes conferring resistance being capable of transfer to heterologous strains, reducing resistance in strains of animal origin should have positive impacts on humans. This article briefly reviews potential roles of non-steroidal anti-inflammatory drugs (NSAIDs), herbal medicines, antimicrobial peptides (AMPs), bacteriophages and their lytic enzymes, vaccination and other emerging therapies for prevention and treatment of mastitis in dairy cows. Although many of these approaches currently lack proven therapeutic efficacy, at least some may gradually replace antibiotics, especially as drug-resistant bacteria are proliferating globally.

Integration of Network Pharmacology and Molecular Docking to Analyse the Mechanism of Action of Oregano Essential Oil in the Treatment of Bovine Mastitis

The active components, potential targets, and mechanisms of action of oregano essential oil in the treatment of bovine mastitis disease were investigated using network pharmacology and molecular docking approaches. The TCMSP and literature databases were examined for the main compounds in oregano essential oil. Afterward, the physical, chemical, and bioavailability characteristics of the components were evaluated. The PubChem, BATMAN, PharmMapper, and Uniprot databases were utilized to predict the target genes of the major components of oregano essential oil. Via the databases of DrugBank, OMIM, GeneCards, TTD, and DisGenet, the disease targets of bovine mastitis were discovered. We analyzed common targets and built protein-protein interaction (PPI) networks using the STRING database. Key genes were analyzed, obtained, and compound-target-pathway-disease visualization networks were created using Cytoscape. For the GO function and KEGG pathway enrichment analysis, the DAVID database was utilized. Molecular docking via Autodock Tools was utilized to evaluate the reliability of the interactions between oregano essential oil and hub targets. Thymol, carvacrol, and p-cymene are the three major components found in oregano essential oil. The potential targets (TNF, TLR4, ALB, IL-1β, TLR2, IL-6, IFNG, and MyD88) were screened according to the visual network. The enrichment analysis suggested that the major signaling pathways in network pharmacology may include PI3K-Akt, MAPK, IL-17, and NF-κ B. Molecular docking analysis shows that thymol had good docking activity with TNF, IL-6, and MyD88, carvacrol had good docking activity with TNF, and p-cymene had good docking activity with ALB. This study clarified the mechanism of action of oregano essential oil in the treatment of bovine mastitis, thus providing data supporting the potential for the use of oregano essential oil in the development of new therapeutics for bovine mastitis.

Effect of Holstein genotype on ex-vivo interleukin-1β response to lipopolysaccharide (LPS), lipoteichoic acid (LTA) and heat-killed Gram-negative and Gram-positive bacteria

Effects of Holstein genotype on interleukin-1β response were assessed by ex-vivo stimulation of whole blood with lipopolysaccharide (LPS), lipoteichoic acid (LTA), or sonicated, heat-killed Gram-negative or Gram-positive bacteria. Holstein genotypes were unselected Holsteins (UH, n = 14) not subjected to selection pressures since the mid-1960s and contemporary Holsteins (CH, n = 13). Milk yield of UH and CH cows differ by more than 4500 kg/lactation. Whole blood was mixed with 0.01 µg LPS, 10 µg LTA or 2.5 × 10⁶ CFU of sonicated, heat-killed E. coli, K. pneumoniae, S. marcescens, S. aureus, S. dysgalactiae, or S. uberis per mL of blood and incubated (4 h, 37 °C). Plasma IL-1β was quantified by ELISA and log₁₀-transformed concentrations analyzed with a multivariate linear mixed effects model. Responses to bacteria were greater than responses to LPS or LTA. Responses to LPS, LTA and the Gram-negative stimulants were greater in UH than in CH cows while responses to the Gram-positive bacteria did not differ between Holstein genotypes. In both genotypes, strong correlations were detected among IL-1β responses to the Gram-negative stimulants and to LTA. There were strong correlations among IL-1β responses to the Gram-positive bacteria in CH cows but only between S. aureus and S. dysgalactiae in UH cows. The IL-1β response to S. uberis was highly correlated with responses to all of the Gram-negative stimulants in CH cows but only with E. coli in the UH cows. The reduced immune response could make contemporary cows more susceptible to infection by Gram-negative bacteria. Results confirm selection practices since the mid-1960s have altered immune response in the Holstein, at least to Gram-negative bacteria, and validate the need for additional studies to further evaluate the impacts of these selection practices on immune function in contemporary Holsteins.

Screening of antibiotic residues in raw bovine milk in Lombardy, Italy: Microbial growth inhibition assay and LC-HRMS technique integration for an accurate monitoring

Antibiotic residues in food of animal origin is a great concern for public health worldwide in terms of antibiotic resistance development, potential allergic reactions and disruption of intestinal flora equilibrium. In this study the presence of antibiotic residues in raw bovine milk samples collected from farms located in Lombardy region in Italy from 2018 to 2022 was assessed in the context of the national milk quality payment system. Samples were screened with microbiological growth inhibition test Delvotest ® SP NT and a very low positivity rate ranging from 0.1% to 0.07% over the four years was determined. A total of 79 positive samples were further analysed by LC-HRMS screening technique to confirm positivity and detect the specific antibiotic compound contaminating the sample. The β-lactam antibiotics resulted to be the most frequently detected, with the penicillin G being the most abundant compound. The data suggested that low levels of antibiotic contamination are consistently maintained over the last four years and the integration of the techniques used in this study is a valuable tool for a deep and precise monitoring of antibiotic residues in milk.

Antimicrobial Usage and Detection of Multidrug-Resistant Staphylococcus aureus: Methicillin- and Tetracycline-Resistant Strains in Raw Milk of Lactating Dairy Cattle

Staphylococcus aureus is a prominent cause of food-borne diseases worldwide. Enterotoxigenic strains of this bacteria are frequently found in raw milk, and some of these strains are resistant to antimicrobials, posing a risk to consumers. The main objectives of this study were to determine the antimicrobial resistance pattern of S. aureus in raw milk and to detect the presence of mecA and tetK genes in it. A total of 150 milk samples were obtained aseptically from lactating cattle, including Holstein Friesian, Achai, and Jersey breeds, maintained at different dairy farms. The milk samples were checked for the presence of S. aureus, and it was detected in 55 (37%) of them. The presence of S. aureus was verified by culturing on selective media, gram staining, and performing coagulase and catalase tests. Further confirmation was performed through PCR with a species-specific thermonuclease (nuc) gene. Antimicrobial susceptibility testing of the confirmed S. aureus was then determined by using the Kirby-Bauer disc diffusion technique. Out of the 55 confirmed S. aureus isolates, 11 were determined to be multidrug-resistant (MDR). The highest resistance was found to penicillin (100%) and oxacillin (100%), followed by tetracycline (72.72%), amikacin (27.27%), sulfamethoxazole/trimethoprim (18.18%), tobramycin (18.18%), and gentamycin (9.09%). Amoxicillin and ciprofloxacin were found to be susceptible (100%). Out of 11 MDR S. aureus isolates, the methicillin resistance gene (mecA) was detected in 9 isolates, while the tetracycline resistance gene (tetK) was found in 7 isolates. The presence of these methicillin- and tetracycline-resistant strains in raw milk poses a major risk to public health, as they can cause food poisoning outbreaks that can spread rapidly through populations. Our study concludes that out of nine empirically used antibiotics, amoxicillin, ciprofloxacin, and gentamicin were highly effective against S. aureus compared to penicillin, oxacillin, and tetracycline.

Resistance Profile of Bovine Mastitis Isolates, Presence of the mecA Gene and Identification of ESBL Producing Strains from Small Rural Dairy Properties

Bovine mastitis is an inflammation of the mammary gland in response to invasion by opportunistic agents. Due to the high economic importance of dairy production and the complexity related to animal health, the objective of this work was to identify and evaluate the antibacterial resistance profile of samples of mastitis milk, milking hand and milking equipment from small rural dairy farms belonging to the northwest region of the state of Paraná, Brazil. Five small, non-technical dairy farms in the municipalities of Boa Esperança, Juranda and Tapejara, all belonging to the northwest region of the state of Paraná, Brazil, were selected. The properties had Holstein and/or crossbred herds, carried out a bucket-by-foot milking system and all had the presence of animals with subclinical mastitis confirmed by the California Mastitis Test. Samples of sterile swabs from the milking insufflators, the milking hand and milk samples were collected-and later, isolation tests and phenotypic characterization of the samples, sensitivity tests to antimicrobials and phenotypic tests for the detection of beta-producing strains were performed with extended-spectrum beta-lactamase (ESBL), molecular identification of Staphylococcus aureus isolates and mecA gene research. Of the 199 samples collected from the 15 selected properties in the municipalities of Boa Esperança, Tapejara and Juranda, 72 (36.20%) were classified as multiresistant. Isolated from milkers' hands and milking machines, which phenotypically produce extended-spectrum beta-lactamase (ESBL), the presence of the mecA gene was also observed in 11 isolates of Staphylococcus spp. of milk samples, machines and milking hands. Mastitis can be spread to the herd through the milking process by the milkers' instruments and hands, and adequate management measures can prevent its transmission and the conscious use of antibiotics decreases the prevalence of multidrug-resistant pathogens. In this work, different pathogenic bacteria were detected in mastitic milk, milking equipment and milking hand with a high percentage (36.20%) of isolates classified as multidrug resistant. In addition, the presence phenotypically (ESBL) and molecularly (mecA gene) of isolates carrying resistance genes was also verified. These results directly reflect on the health of the animals, the health of the workers and the health of the respective environment, which can enable the continuity of the propagation of the etiological agents involved in the mastitis infection. The awareness of producers and workers on these properties about the disease, transmission, sanitary aspects and adequate management and treatment are essential for improving milk production and production efficiency.

Analysis of differentially expressed microRNAs in bovine mammary epithelial cells treated with lipoteichoic acid

Mastitis is one of the most common diseases of dairy cattle and can be caused by physical stress, chemicals and microbial infection. Staphylococcus aureus is the most common pathogens that induce mastitis in dairy cattle. In this study, bovine mammary epithelial cells (BMECs) were treated either with lipoteichoic acid (LTA, 30 µg/ml) or 1 × phosphate-buffer saline (PBS, control) and RNA-Seq was applied to explore the effect of LTA on the expression microRNAs (miRNAs) in BMECs. Compared to the control group, 43 miRNAs were significantly up-regulated and eight miRNAs were significantly down-regulated. Additionally, 724 genes were significantly up-regulated and 13 genes were significantly down-regulated in LTA group relative to the control group. Bta-miR-196a, bta-miR-2285aj-5p, bta-miR-143, bta-miR-2433, bta-miR-2284f and bta-miR-2368-3p were selected from 51 differentially expressed miRNAs and are discussed in this manuscript. Target gene prediction revealed that the target genes of these six miRNAs were all differentially expressed, including MT1E, SPDYA, FGL1, TLR2, PAPOLG, ZDHHC17 and SMC4. Subsequently, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the target genes with differentially expressed miRNAs were enriched in mitogen-activated protein kinase (MAPK) signalling pathway, rheumatoid arthritis and cancer. Therefore, the results of this study provided new evidences for the molecular mechanism of LTA-induced mastitis, which may provide new targets for the diagnosis and treatment of mastitis in dairy cattle.

SERS-based immunosensor for E. coli contaminants detection in milk using silver-coated nanoporous silicon substrates

The dairy sector is frequently affected by contagious and environmental factors that spread between animals by numerous means and induce the inflammatory disease of bovine mastitis (BM). Herein, silver decorated porous silicon (Ag-pSi) SERS platform was designed for rapid and reliable Escherichia coli (predominant BM pathogen) detection in various milk origins. The inherent surface void and pore morphology were physically optimized to augment the SERS effect using 4-aminothiphenol (4ATP) while achieving an enhancement factor >4.6 × 10⁷. An indirect immunoassay evaluated the residual unreacted antibodies using an optimized 4ATP/Ag-pSi SERS platform modified with secondary antibodies. Under optimized conditions, the porous substrate offered high sensitivity toward target bacteria detection of 3 CFU mL^-1 and linear response of 10¹-10⁵ CFU mL^-1. Moreover, the selectivity and specificity of the designed sensing platform were cross-validated against other interfering bacteria without compromising its performance efficiencies. Finally, the applicability of the developed system for real-life conditions was elucidated in different milk samples (bovine, goat, sheep) with recovery values of 78-115% compared to the conventional culture technique. Considering the complex media analysis, the miniaturized SERS platform is highly reliable, rapid and accurate that could be applicable for routine on-site analysis of various emerging pathogens relevant to BM management.

Immunological and Oxidative Biomarkers in Bovine Serum from Healthy, Clinical, and Sub-Clinical Mastitis Caused by Escherichia coli and Staphylococcus aureus Infection

The study aimed to investigate the mastitis' emerging causative agents and their antimicrobial sensitivity, in addition to the hematological, biochemical indicators, oxidative biomarkers, acute phase protein (APP), and inflammatory cytokine changes in dairy farms in Gamasa, Dakahlia Governorate, Egypt. One hundred Holstein Friesian dairy cattle with clinical and subclinical mastitis were investigated and were allocated into three groups based on a thorough clinical examination. Escherichia coli and Staphylococcus aureus were found responsible for the clinical and subclinical mastitis in dairy farms, respectively. Multiple drug resistance (MDR) was detected in 100%, and 94.74% of E. coli and S. aureus isolates, respectively. Significantly low RBCs count, Hb, and PCV values were detected in mastitic cows compared with both subclinical mastitic and control groups; moreover, WBCs, lymphocytes, and neutrophil counts were significantly diminished in mastitic cows compared to the controls. Significantly higher levels of AST, LDH, total protein, and globulin were noticed in both mastitic and subclinical mastitic cows. The haptoglobin, fibrinogen, amyloid A, ceruloplasmin, TNF-α, IL-1β, and IL-6 levels were statistically increased in mastitic cows compared to the controls. Higher MDA levels and reduction of TAC and catalase were identified in all the mastitic cases compared to the controls. Overall, the findings suggested potential public health hazards due to antimicrobial resistance emergence. Meanwhile, the APP and cytokines, along with antioxidant markers can be used as early indicators of mastitis.

Is AMR in Dairy Products a Threat to Human Health? An Updated Review on the Origin, Prevention, Treatment, and Economic Impacts of Subclinical Mastitis

Background

Bovine mastitis is the most frequent and costly illness impacting dairy herds worldwide. The presence of subclinical mastitis in dairy cows has an impact on the decreased output of milk and milk quality, culling of affected cows, mortality rate, as well as mastitis-related treatment expenses, generating significant financial loss to the dairy industry. The pathogenic bacteria invade through the mammary gland, which then multiply in the milk-producing tissues causing infection, and the presence of pathogenic bacteria in milk is concerning, jeopardizes human health, and also has public health consequences. Intervention to promote herd health is essential to protect public health and the economy.

Results

This review attempts to provide an overview of subclinical mastitis, including mastitis in different species, the effect of mastitis on human health and its pathogenic mechanism, the prevalence and incidence of subclinical mastitis, and current preventive, diagnostic, and treatment methods for subclinical mastitis. It also elaborates on the management practices that should be followed by the farms to improve herd immunity and health.

Conclusion

This review brings the importance of the threat of antimicrobial resistance organisms to the dairy industry. Furthermore, this review gives a glimpse of the economic consequences faced by the farmers and a futuristic mastitis market analysis in the dairy industry.

Effect of forsythoside A on the transcriptional profile of bovine mammary epithelial cells challenged with lipoteichoic acid

Mastitis is a common disease of the dairy cattle, which affects the development of the dairy industry and leads to huge economic losses. Forsythoside A (FTA) has anti-inflammatory, antioxidant, antiviral and anti-apoptotic effects. However, the therapeutic effect and molecular mechanism of FTA on dairy cow mastitis remain unclear. In this study, bovine mammary epithelial cells (BMECs) were stimulated with lipoteichoic acid (LTA), a key virulence factor of Staphylococcus aureus (S. aureus), to construct in vitro models, and then treated with FTA. Subsequently, the differentially expressed genes (DEGs) in different groups were determined by RNA sequencing (RNA-Seq) analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyse the possible function of the DEGs, real-time quantitative PCR (RT-qPCR) was used to verify whether the expression levels of these DEGs were consistent with RNA-Seq results. The results showed that cell division cycle 20B (CDC20B), endothelial cell surface expressed chemotaxis and apoptosis regulator (ECSCR), complement factor H-related 5 (CFHR5) and phospholipase A2 group IVA (PLA2G4A) were down-regulated after FTA treatment. In contrast, Kruppel-like factor 15 (KLF15) and Metallothionein 1E (MT1E) were up-regulated. These DEGs are involved in processes such as apoptosis, inflammation and development of cancer. This study provides valuable insights into the transcriptome changes in BMECs after FTA treatment. Further analysis may help identify the underlying molecular mechanisms.

MALDI-TOF mass spectrometry profiling of bovine skim milk for subclinical mastitis detection

Introduction

Mastitis is one of most impacting health issues in bovine dairy farming that reduces milk yield and quality, leading to important economic losses. Subclinical forms of the disease are routinely monitored through the measurement of somatic cell count (SCC) and microbiological tests. However, their identification can be tricky, reducing the possibilities of early treatments. In this study, a MALDI-TOF mass spectrometry approach was applied to milk samples collected from cows classified according to the SCC, to identify differences in polypeptide/protein profiles.

Materials and methods

Twenty-nine raw milk samples with SCC &gt;200,000 cell/ml (group H) and 91 samples with SCC lower than 200,000 (group L) were randomly collected from 12 dairy farms. Spectral profiles from skim milk were acquired in the positive linear mode within the 4,000–20,000 m/z mass acquisition range.

Results and discussion

Based on signal intensity, a total of 24 peaks emerged as significant different between the two groups. The most discriminant signals (4,218.2 and 4,342.98 m/z) presented a ROC curve with AUC values higher than 0.8. Classification algorithms (i.e., quick classifier, genetic algorithm, and supervised neural network) were applied for generating models able to classify new spectra (i.e., samples) into the two classes. Our results support the MALDI-TOF mass spectrometry profiling as a tool to detect mastitic milk samples and to potentially discover biomarkers of the disease. Thanks to its rapidity and low-cost, such method could be associated with the SCC measurement for the early diagnosis of subclinical mastitis.

FABP4-mediated lipid droplet formation in Streptococcus uberis-infected macrophages supports host defence

Foamy macrophages containing prominent cytoplasmic lipid droplets (LDs) are found in a variety of infectious diseases. However, their role in Streptococcus uberis-induced mastitis is unknown. Herein, we report that S. uberis infection enhances the fatty acid synthesis pathway in macrophages, resulting in a sharp increase in LD levels, accompanied by a significantly enhanced inflammatory response. This process is mediated by the involvement of fatty acid binding protein 4 (FABP4), a subtype of the fatty acid-binding protein family that plays critical roles in metabolism and inflammation. In addition, FABP4 siRNA inhibitor cell models showed that the deposition of LDs decreased, and the mRNA expression of Tnf, Il1b and Il6 was significantly downregulated after gene silencing. As a result, the bacterial load in macrophages increased. Taken together, these data demonstrate that macrophage LD formation is a host-driven component of the immune response to S. uberis. FABP4 contributes to promoting inflammation via LDs, which should be considered a new target for drug development to treat infections.

Selenomethionine protected BMECs from inflammatory injury and oxidative damage induced by Klebsiella pneumoniae by inhibiting the NF-κB and activating the Nrf2 signaling pathway

Klebsiella pneumoniae (K. pneumoniae) is one of the main environmental pathogens causing bovine mastitis. The incidence of bovine mastitis caused by K. pneumoniae is increasing worldwide. Selenium is an essential trace element that has multiple physiological functions, such as antioxidant and anti-inflammatory activities. Therefore, this study aimed to verify whether selenomethionine (SeMet) could contribute to alleviating the inflammatory injury and oxidative damage induced by K. pneumoniae. Bovine mammary epithelial cells were cultured in vitro and pretreated with 4 μM SeMet before being infected with K. pneumoniae. Western blot analysis was used to detect the expression of the related proteins in the NF-κB and Nrf2 signaling pathways. The gene expression levels of IL-1β, IL-6, IL-8, TNF-α, Nrf2, Keap1, NQO-1 and HO-1 were detected using RT-qPCR. The levels of MDA, GSH-PX, SOD, CAT and T-AOC were detected by commercial assay kits. Flow cytometry was used to determine the level of intracellular ROS, and immunofluorescence was used to detect the nuclear localization of Nrf2 protein. Briefly, SeMet downregulated the phosphorylation levels of IκBα and p65 proteins and the gene expression levels of IL-1β, IL-6, IL-8 and TNF-α were also decreased. Moreover, the protein and gene expression levels of Nrf2, NQO-1 and HO-1 were upregulated, and the nuclear expression of Nrf2 protein was also promoted, which enhanced the activity of antioxidant enzymes. In conclusion, SeMet protected BMECs from inflammatory injury and oxidative stress induced by K. pneumoniae by inhibiting the NF-κB and activating the Nrf2 signaling pathway.

Moringa concanensis-Mediated Synthesis and Characterizations of Ciprofloxacin Encapsulated into Ag/TiO2/Fe2O3/CS Nanocomposite: A Therapeutic Solution against Multidrug Resistant E. coli Strains of Livestock Infectious Diseases

Background: Multidrug resistant MDR bacterial strains are causing fatal infections, such as mastitis. Thus, there is a need for the development of new target-oriented antimicrobials. Nanomaterials have many advantages over traditional antibiotics, including improved stability, controlled antibiotic release, targeted administration, enhanced bioavailability, and the use of antibiotic-loaded nanomaterials, such as the one herein reported for the first time, appear to be a promising strategy to combat antibiotic-resistant bacteria. The use of rationally designed metallic nanocomposites, rather than the use of single metallic nanoparticles (NPs), should further minimize the bacterial resistance. Aim: Green synthesis of a multimetallic/ternary nanocomposite formed of silver (Ag), titanium dioxide (TiO2), and iron(III) oxide (Fe2O3), conjugated to chitosan (CS), in which the large spectrum fluoroquinolone antibiotic ciprofloxacin (CIP) has been encapsulated. Methods: The metallic nanoparticles (NPs) Ag NPs, TiO2 NPs, and Fe2O3 NPs were synthesized by reduction of Moringa concanensis leaf aqueous extract. The ternary junction was obtained by wet chemical impregnation technique. CIP was encapsulated into the ternary nanocomposite Ag/TiO2/Fe2O3, followed by chitosan (CS) conjugation using the ionic gelation method. The resulting CS-based nanoparticulate drug delivery system (NDDS), i.e., CIP-Ag/TiO2/Fe2O3/CS, was characterized in vitro by gold standard physical techniques such as X-ray diffractometry (XRD), field emission scanning electron microscopy (FESEM), Fourier-transform infrared (FTIR) spectroscopy. Pharmacological analyses (i.e., LC, EE, ex-vivo drug release behavior) were also assessed. Further, biological studies were carried out both ex vivo (i.e., by disk diffusion method (DDM), fluorescence-activated single cell sorting (FACS), MTT assay) and in vivo (i.e., antibacterial activity in a rabbit model, colony-forming unit (CFU) on blood agar, histopathological analysis using H&E staining). Results: The encapsulation efficiency (EE) and the loading capacity (LC) of the NDDS were as high as 94% ± 1.26 and 57% ± 3.5, respectively. XRD analysis confirmed the crystalline nature of the prepared formulation. FESEM revealed nanorods with an average diameter of 50−70 ± 12 nm. FTIR confirmed the Fe-O-Ti-CS linkages as well as the successful encapsulation of CIP into the NDDS. The zeta potential (ZP) of the NDDS was determined as 85.26 ± 0.12 mV. The antimicrobial potential of the NDDS was elicited by prominent ZIs against MDR E. coli (33 ± 1.40 mm) at the low MIC of 0.112 μg/mL. Morphological alterations (e.g., deformed shape and structural damages) of MDR pathogens were clearly visible overtime by FESEM after treatment with the NDDS at MIC value, which led to the cytolysis ultimately. FACS analysis confirmed late apoptotic of the MDR E. coli (80.85%) after 6 h incubation of the NDDS at MIC (p < 0.05 compared to untreated MDR E. coli used as negative control). The highest drug release (89% ± 0.57) was observed after 8 h using PBS medium at pH 7.4. The viability of bovine mammary gland epithelial cells (BMGE) treated with the NDDS remained superior to 90%, indicating a negligible cytotoxicity (p < 0.05). In the rabbit model, in which infection was caused by injecting MDR E. coli intraperitoneally (IP), no colonies were detected after 72 h of treatment. Importantly, the histopathological analysis showed no changes in the vital rabbit organs in the treated group compared to the untreated group. Conclusions: Taken together, the newly prepared CIP-Ag/TiO2/Fe2O3/CS nanoformulation appears safe, biocompatible, and therapeutically active to fight MDR E. coli strains-causing mastitis.

nor 3′-Demethoxyisoguaiacin from Larrea tridentata Is a Potential Alternative against Multidrug-Resistant Bacteria Associated with Bovine Mastitis

Bovine mastitis is one of the most common diseases in dairy cows, and it causes significant economic losses in dairy industries worldwide. Gram-positive and Gram-negative bacteria can cause bovine mastitis, and many of them have developed antimicrobial resistance. There is an urgent need for novel therapeutic options to treat the disease. Larrea tridentata-derived compounds represent an important potential alternative treatment. The aim of the present study was to isolate and characterize antibacterial compounds from Larrea tridentata against multidrug-resistant bacteria associated with bovine mastitis. The L. tridentata hydroalcoholic extract (LTHE) exhibited antibacterial activity. The extract was subjected to a bipartition, giving an aqueous fraction (moderate antibacterial activity) and an organic fraction (higher antibacterial activity). Chromatographic separation of the organic fraction enabled us to obtain four active sub-fractions. Chemical analyses through HPLC techniques were conducted for the LTHE, fractions, and sub-fraction Ltc1-F3, from which we isolated two compounds, characterized by ¹H and ¹³C NMR analyses. Compound nor-3 demethoxyisoguaiacin exhibited the best antibacterial activity against the evaluated bacteria (MIC: 0.01–3.12 mg/mL; MBC: 0.02–3.12 mg/mL). The results indicated that nor-3 demethoxyisoguaiacin can be used as an alternative treatment for multidrug-resistant bacteria associated with mastitis.

Sulfur Amino Acid Metabolism and the Role of Endogenous Cystathionine-γ-lyase/H2S in Holstein Cows with Clinical Mastitis

H2S plays an important role in various inflammatory diseases. However, the role of H2S and synthetic enzymes in Holstein cows with CM is unknown. The aim of this study was to identify DEPs associated with sulfide metabolism and further investigate their roles in dairy cows with CM. From 3739 DEPs generated by data-independent acquisition proteomics, we identified a total of 17 DEPs included in 44 GO terms and five KEGG pathways related to sulfide metabolism, including CTH and cystathionine-β-synthase (CBS). Immunohistochemical and immunofluorescence staining results showed that CTH and CBS proteins were present mainly in the cytoplasm of mammary epithelial cells. Endogenous H2S production in the serum of the CM group was significantly lower than that of the healthy Holstein cows. CTH and CBS mRNA and protein levels in the mammary glands of the CM group were significantly downregulated compared to those of the healthy group. These results indicate that CTH and H2S were correlated with the occurrence and development of CM in Holstein cows, which provides important insights into the function and regulatory mechanism of CTH/H2S in Holstein cows.

Differential mRNA Expression Profiling Reveals the Role of MiR-375 in Inflammation of Bovine Mammary Epithelial Cells

Simple Summary

Bovine mammary epithelial cells (bMECs) are often used as cell models for mammary gland research. They are the most important cells for mammary gland function and the first line of defense for pathogen identification. MicroRNAs (miRNAs) are important regulatory factors involved in many physiological and pathological processes. Here, we examined a transcriptome profile of bovine mammary epithelial cell lines transfected with miR-375 inhibitor or negative control (NC) inhibitor, and further reveal the potential role of miR-375 in bMECs by differentially expressed mRNA analysis. We found that miR-375 potentially promotes inflammation in the mammary gland through the MAPK signaling pathway.

Abstract

MicroRNAs (miRNAs) are a class of small non-coding RNAs that regulate post-transcriptional gene expression and several biological processes. Bovine mammary epithelial cells (bMECs) mediate critical immune responses in the mammary gland and the occurrence of mastitis. Current research focuses on miRNA regulation of bMECs, but the miR-375 regulatory mechanism in bMECs is unclear. This study explored the role of miR-375 by profiling the transcriptome of miR-375-silenced bMECs using RNA-seq and identifying differentially expressed mRNAs (DIE-mRNAs). There were 63 DIE-mRNAs, including 48 down-regulated and 15 up-regulated mRNAs between miR-375-silenced bMECs and the controls. The Kyoto encyclopedia of genes and genomes (KEGG) and Gene Ontology (GO) functional analysis showed that the DIE-mRNAs enriched nuclear receptor subfamily 4 group A member 1 (NR4A1) and protein tyrosine phosphatase non-receptor type 5 (PTPN5) anti-inflammatory genes of the mitogen-activated protein kinase (MAPK) signaling pathway. However, they showed an opposite trend to the expression of miR-375 silencing, suggesting that miR-375 promotes bMEC inflammation through the MAPK signaling pathway. The findings of this study provide a new reference for understanding the regulation of bMEC inflammation and cow mastitis.

Progress in Expression Pattern and Molecular Regulation Mechanism of LncRNA in Bovine Mastitis

Simple Summary

Bovine mastitis is an inflammatory disease of the mammary glands that causes serious harm to cow health and huge economic losses. Susceptibility or resistance to mastitis in individual cows is mainly determined by genetic factors, including coding genes and non-coding genes. Long non-coding RNAs (lncRNAs) are non-coding RNA molecules with a length of more than 200 nucleotides (nt) that have recently been discovered. They can regulate a variety of diseases of humans and animals, especially the immune response and inflammatory disease process. This paper reviews the role of long non-coding RNA (lncRNA) in inflammatory diseases, emphasizes on the latest research progress of lncRNA expression and the molecular regulatory mechanism in bovine mastitis, and looks forward to the research and application prospect of lncRNA in bovine mastitis, intending to provide a reference for scientific researchers to systematically understand this research field.

Abstract

Bovine mastitis is an inflammatory disease caused by pathogenic microbial infection, trauma, or other factors. Its morbidity is high, and it is difficult to cure, causing great harm to the health of cows and the safety of dairy products. Susceptibility or resistance to mastitis in individual cows is mainly determined by genetic factors, including coding genes and non-coding genes. Long non-coding RNAs (lncRNAs) are a class of endogenous non-coding RNA molecules with a length of more than 200 nucleotides (nt) that have recently been discovered. They can regulate the immune response of humans and animals on three levels (transcription, epigenetic modification, and post-transcription), and are widely involved in the pathological process of inflammatory diseases. Over the past few years, extensive findings revealed basic roles of lncRNAs in inflammation, especially bovine mastitis. This paper reviews the expression pattern and mechanism of long non-coding RNA (lncRNA) in inflammatory diseases, emphasizes on the latest research progress of the lncRNA expression pattern and molecular regulatory mechanism in bovine mastitis, analyzes the molecular regulatory network of differentially expressed lncRNAs, and looks forward to the research and application prospect of lncRNA in bovine mastitis, laying a foundation for molecular breeding and the biological therapy of bovine mastitis.

Efficacy Evaluation of a Combined Hemorrhagic Septicemia-Mastitis Vaccine in Dairy Cows and Buffaloes

Hemorrhagic septicemia (HS) and mastitis caused by Pasteurella (P.) multocida, Staphylococcus (S.) aureus and Streptococcus (Str.) agalactiae are important ailments of the dairy industry especially in South Asia. The present study evaluates the efficacy of a locally prepared hemorrhagic septicemia (HS) and mastitis combined vaccine. To this end, a total of 70 HS, S. aureus and Str. agalactiae-free lactating (early stage of lactation) buffaloes (n = 45) and cows (n = 25), and 50 lactating (early stage of lactation) cows (n = 25) and buffaloes (n = 25) positive for S. aureus/Str. agalactiae were subjected to two doses of HS−mastitis combined vaccine with an interval of 21 days. Antibody response was monitored by ELISA up to six months (180 days). Antibody titers against HS and mastitis were significantly (p ˂ 0.05) higher in vaccinated groups as compared to the non-vaccinated groups. Cumulative mean somatic cell counts and mastitis severity scores in vaccinated groups were significantly lower (p < 0.05), and milk yield was significantly higher (p < 0.05) than those in the respective non-vaccinated controls. In conclusion, Montanide®-adjuvanted HS−mastitis combined vaccine showed significant immunogenic effects in dairy cows and buffaloes. However, challenge studies remain overdue.

Frequently used therapeutic antimicrobials and their resistance patterns on Staphylococcus aureus and Escherichia coli in mastitis affected lactating cows

Mastitis is one of the most frequent and costly production diseases of dairy cattle. It is frequently treated with broad-spectrum antimicrobials. The objectives of this work were to investigate the prevalence of Staphylococcus aureus and Escherichia coli, find out the antimicrobials used in mastitis treatment, and explore the antimicrobial resistance profile including detection of resistance genes. Bacterial species and antimicrobial resistance genes were confirmed by the polymerase-chain reaction. A total of 450 cows were screened, where 23 (5.11%) and 173 (38.44%) were affected with clinical and sub-clinical mastitis, respectively. The prevalence of S. aureus was 39.13% (n = 9) and 47.97%(n = 83) while, E. coli was 30.43% (n = 7) and 15.60% (n = 27) in clinical and sub-clinical mastitis affected cows, respectively. The highest antimicrobials used for mastitis treatment were ciprofloxacin (83.34%), amoxycillin (80%) and ceftriaxone (76.67%). More than, 70% of S. aureus showed resistance against ampicillin, oxacillin, and tetracycline and more than 60% of E. coli exhibited resistance against oxacillin and sulfamethoxazole-trimethoprim. Selected antimicrobial resistance genes (mecA, tetK, tetL, tetM, tetA, tetB, tetC, sul1, sul2 and sul3) were identified from S. aureus and E. coli. Surprisingly, 7 (7.61%) S. aureus carried the mecA gene and were confirmed as methicillin-resistant S. aureus (MRSA). The most prevalent resistance genes were tetK 18 (19.57%) and tetL 13 (14.13%) for S. aureus, whereas sul1 16 (47.06%), tetA 12 (35.29%), sul2 11 (32.35%) and tetB 7 (20.59%) were the most common resistance genes in E. coli. Indiscriminate use of antimicrobials and the presence of multidrug-resistant bacteria suggest a potential threat to public health.

N6-Methyladenosine Modification Profile in Bovine Mammary Epithelial Cells Treated with Heat-Inactivated Staphylococcus aureus

The symptoms of mastitis caused by Staphylococcus aureus (S. aureus) in dairy cows are not obvious and difficult to identify, resulting in major economic losses. N6-Methyladenosine (m6A) modification has been reported to be closely associated with the occurrence of many diseases. However, only a few reports have described the role of m6A modification in S. aureus-induced mastitis. In this study, after 24 h of treatment with inactivated S. aureus, MAC-T cells (an immortalized bovine mammary epithelial cell line) showed increased expression levels of the inflammatory factors IL-1β, IL-6, TNF-α, and reactive oxygen species. We found that the mRNA levels of METLL3, METLL14, WTAP, and ALKBH5 were also upregulated. Methylated RNA immunoprecipitation sequencing analysis revealed that 133 genes were m6A hypermethylated, and 711 genes were m6A hypomethylated. Biological functional analysis revealed that the differential m6A methylated genes were mainly related to oxidative stress, lipid metabolism, inflammatory response, and so on. In the present study, we also identified 62 genes with significant changes in m6A modification and mRNA expression levels. These findings elucidated the m6A modification spectrum induced by S. aureus in MAC-T cells and provide the basis for subsequent m6A research on mastitis.

LAP-MALDI MS coupled with machine learning: an ambient mass spectrometry approach for high-throughput diagnostics

Large-scale population screening for early and accurate detection of disease is a key objective for future diagnostics. Ideally, diagnostic tests that achieve this goal are also cost-effective, fast and easily adaptable to new diseases with the potential of multiplexing. Mass spectrometry (MS), particularly MALDI MS profiling, has been explored for many years in disease diagnostics, most successfully in clinical microbiology but less in early detection of diseases. Here, we present liquid atmospheric pressure (LAP)-MALDI MS profiling as a rapid, large-scale and cost-effective platform for disease analysis. Using this new platform, two different types of tests exemplify its potential in early disease diagnosis and response to therapy. First, it is shown that LAP-MALDI MS profiling detects bovine mastitis two days before its clinical manifestation with a sensitivity of up to 70% and a specificity of up to 100%. This highly accurate, pre-symptomatic detection is demonstrated by using a large set of milk samples collected weekly over six months from approximately 500 dairy cows. Second, the potential of LAP-MALDI MS in antimicrobial resistance (AMR) detection is shown by employing the same mass spectrometric setup and similarly simple sample preparation as for the early detection of mastitis.

2-Methyl Nonyl Ketone From Houttuynia Cordata Thunb Alleviates LPS-Induced Inflammatory Response and Oxidative Stress in Bovine Mammary Epithelial Cells

Mastitis is one of the most common diseases in dairy cows, causing huge economic losses to the dairy industry every year. Houttuynia Cordata Thunb (H.cordata) is a traditional Chinese herbal medicine that is widely used in clinical treatment. However, the therapeutic effect of 2-methyl nonyl ketone (MNK), the main volatile oil component in the aqueous vapor extract of H. cordata, on mastitis has been less studied. The purpose of this study was to investigate the protective effect and mechanism of MNK against lipopolysaccharide (LPS)-induced mastitis in vitro. The results showed that MNK pretreatment of the bovine mammary epithelial cell line (MAC-T) enhanced cell viability and inhibited LPS-induced reactive oxygen species (ROS) production and inflammatory response. MNK reduced the production of pro-inflammatory cytokines such as interleukin (IL) and tumor necrosis factor-α (TNF-α) by repressing LPS-induced activation of Toll-like receptor 4-nuclear factor-κB (TLR4-NF-κB) signaling pathway. In addition, MNK protected cells from inflammatory responses by blocking the downstream signaling of inflammatory factors. MNK also induced Heme Oxygenase-1 (HO-1) production by Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway through AKT and extracellular signal-regulated kinase (ERK) pathways, thereby reducing LPS-induced oxidative damage for MAC-T cells. In conclusion, MNK played a protective role against LPS-induced cell injury. This provides a theoretical basis for the research and development of MNK as a novel therapeutic agent for mastitis.

Differential Expression Profiles of lncRNA Following LPS-Induced Inflammation in Bovine Mammary Epithelial Cells

Bovine mastitis is an inflammatory response of mammary glands caused by pathogenic microorganisms such as Escherichia coli (E. coli). As a key virulence factor of E. coli, lipopolysaccharide (LPS) triggers innate immune responses via activation of the toll-like-receptor 4 (TLR4) signaling pathway. However, the molecular regulatory network of LPS-induced bovine mastitis has yet to be fully mapped. In this study, bovine mammary epithelial cell lines MAC-T were exposed to LPS for 0, 6 and 12 h to assess the expression profiles of long non-coding RNAs (lncRNAs) using RNA-seq. Differentially expressed lncRNAs (DElncRNAs) were filtered out of the raw data for subsequent analyses. A total of 2,257 lncRNAs, including 210 annotated and 2047 novel lncRNAs were detected in all samples. A large proportion of lncRNAs were present in a high abundance, and 112 DElncRNAs were screened out at different time points. Compared with 0 h, there were 22 up- and 25 down-regulated lncRNAs in the 6 h of post-infection (hpi) group, and 27 up- and 22 down-regulated lncRNAs in the 12 hpi group. Compared with the 6 hpi group, 32 lncRNAs were up-regulated and 25 lncRNAs were down-regulated in the 12 hpi group. These DElncRNAs are involved in the regulation of a variety of immune-related processes including inflammatory responses bMECs exposed to LPS. Furthermore, lncRNA TCONS_00039271 and TCONS_00139850 were respectively significance down- and up-regulated, and their target genes involve in regulating inflammation-related signaling pathways (i.e.,Notch, NF-κB, MAPK, PI3K-Akt and mTOR signaling pathway), thereby regulating the occurrence and development of E. coli mastitis. This study provides a resource for lncRNA research on the molecular regulation of bovine mastitis.

Anti-Inflammatory and Antibacterial Potential of Qicao Rukang Powder in Bovine Subclinical Mastitis

Background

Subclinical mastitis is one of the most common reproductive diseases in dairy cows. Qicao Rukang powder is a Chinese herbal compound mixture developed to treat subclinical mastitis in dairy cows by clearing heat, tonifying qi, and improving blood and milk circulation. The study aimed to determine the anti-inflammatory and antimicrobial efficacy of Qicao Rukang powder in treating subclinical mastitis in dairy cows at the manufacturer's recommended dose.

Methods

Forty (40) Holstein dairy cows with milk somatic cell count (SCC) ≥ 500,000 cellml⁻¹ were randomly assigned to treatment (n = 20) and control (n = 20) groups. Cows in the treatment group were administered with 150 grams of Qicao Rukang powder orally for five days, while the control group received no treatment. The authors analyzed the milk SCC, milk composition, bacteriological cure rate of the drug, blood serum levels of interleukins (IL-6, IL-1β, and IL-8), tumor necrosis factor (TNF-α), and interferon gamma (INF-γ) quantified by using ELISA kits on day 0 and day 6.

Results

SCC of the treated group reduced very significantly (P < 0.001) compared with the control group. Milk fat, protein, and total solids increased significantly (P < 0.05) after treatment, whereas lactose and milk urea nitrogen levels showed a nonsubstantial rise. The bacteriological cure percentage of Qicao Rukang powder therapy was 77.8% for Aeromonas spp. (14 of 18), 75% for Pseudomonas spp. (6 of 8), and 100% for Acinetobacter spp. and Enterococcus spp. giving 81.8% cured for all isolates (27 of 33). Only 26.7% (8 of 30) of untreated cows recovered spontaneously. Analysis of IL-1β, IL-6, and INF-γ in the blood serum of the treated group revealed a significant decrease (P < 0.01) with nonsignificant rises in TNF-α and IL-8 levels.

Conclusions

This research demonstrates that Qicao Rukang powder has potent antibacterial and anti-inflammatory actions, supporting its use as an alternative to conventional treatment for subclinical dairy cow mastitis. However, further investigations will be required to explain the role of the active ingredients and the mechanisms involved in the pharmacological activities of the Qicao Rukang powder.

Milk Lactose as a Biomarker of Subclinical Mastitis in Dairy Cows

Bovine subclinical mastitis can cause great harm to dairy herds because of its negative impact on milk production and quality and cow health. Improved diagnostic tools are needed to maximise the control of subclinical mastitis distribution and ensure the high quality of milk as an industrial product. Between 2015 and 2020, seventy-two dairy herds were screened for bovine subclinical mastitis causative agents to identify the relationship between seasons, lactose levels and subclinical mastitis infection. The predominant species found in the milk samples were mixed microbiota, coagulase-negative Staphylococcus and Staphylococcus aureus. Yeasts were found exclusively in autumn, while Enterococcus spp. and Escherichia coli were only found in summer and autumn. A negative correlation was detected between milk lactose and number of somatic cells in milk (-0.471; p < 0.001). The lactose levels in milk were closely associated with the prevalence (%) of subclinical mastitis pathogens, such as Streptococcus agalactiae (y = -1.8011x + 10.867, R2 = 0.9298), Staph. aureus (y = -3.5216x + 25.957, R2 = 0.8604) and other Streptococci (y = -0.5956x + 7.6179, R2 = 0.6656). These findings suggest that milk lactose may be used as a biomarker of suspected udder inflammation in modern health prevention programmes for cows to reduce the prevalence of subclinical mastitis pathogens in dairy cattle herds.

Transcriptome Profiling of m6A mRNA Modification in Bovine Mammary Epithelial Cells Treated with Escherichia coli

Mastitis is a common disease in dairy cows that is mostly caused by E. coli, and it brings massive losses to the dairy industry. N⁶-Methyladenosine (m⁶A), a methylation at the N⁶ position of RNA adenine, is a type of modification strongly associated with many diseases. However, the role of m⁶A in mastitis has not been investigated. In this study, we used MeRIP-seq to sequence the RNA of bovine mammary epithelial cells treated with inactivated E. coli for 24 h. In this in vitro infection model, there were 16,691 m⁶A peaks within 7066 mRNA transcripts in the Con group and 10,029 peaks within 4891 transcripts in the E. coli group. Compared with the Con group, 474 mRNAs were hypermethylated and 2101 mRNAs were hypomethylated in the E. coli group. Biological function analyses revealed differential m⁶A-modified genes mainly enriched in the MAPK, NF-κB, and TGF-β signaling pathways. In order to explore the relationship between m⁶A and mRNA expression, combined MeRIP-seq and mRNA-seq analyses revealed 212 genes with concomitant changes in the mRNA expression and m⁶A modification. This study is the first to present a map of RNA m⁶A modification in mastitis treated with E. coli, providing a basis for future research.

Advances in therapeutic and managemental approaches of bovine mastitis: a comprehensive review

Mastitis (intramammary inflammation) caused by infectious pathogens is still considered a devastating condition of dairy animals affecting animal welfare as well as economically incurring huge losses to the dairy industry by means of decreased production performance and increased culling rates. Bovine mastitis is the inflammation of the mammary glands/udder of bovines, caused by bacterial pathogens, in most cases. Routine diagnosis is based on clinical and subclinical forms of the disease. This underlines the significance of early and rapid identification/detection of etiological agents at the farm level, for which several diagnostic techniques have been developed. Therapeutic regimens such as antibiotics, immunotherapy, bacteriocins, bacteriophages, antimicrobial peptides, probiotics, stem cell therapy, native secretory factors, nutritional, dry cow and lactation therapy, genetic selection, herbs, and nanoparticle technology-based therapy have been evaluated for their efficacy in the treatment of mastitis. Even though several strategies have been developed over the years for the purpose of managing both clinical and subclinical forms of mastitis, all of them lacked the efficacy to eliminate the associated etiological agent when used as a monotherapy. Further, research has to be directed towards the development of new therapeutic agents/techniques that can both replace conventional techniques and also solve the problem of emerging antibiotic resistance. The objective of the present review is to describe the etiological agents, pathogenesis, and diagnosis in brief along with an extensive discussion on the advances in the treatment and management of mastitis, which would help safeguard the health of dairy animals.

Nanomaterials and Essential Oils as Candidates for Developing Novel Treatment Options for Bovine Mastitis

Nanomaterials have been used for diagnosis and therapy in the human medical field, while their application in veterinary medicine and animal production is still relatively new. Nanotechnology, however, is a rapidly growing field, offering the possibility of manufacturing new materials at the nanoscale level, with the formidable potential to revolutionize the agri-food sector by offering novel treatment options for prevalent and expensive illnesses such as bovine mastitis. Since current treatments are becoming progressively more ineffective in resistant bacteria, the development of innovative products based on both nanotechnology and phytotherapy may directly address a major global problem, antimicrobial resistance, while providing a sustainable animal health solution that supports the production of safe and high-quality food products. This review summarizes the challenges encountered presently in the treatment of bovine mastitis, emphasizing the possibility of using new-generation nanomaterials (e.g., biological synthesized nanoparticles and graphene) and essential oils, as candidates for developing novel treatment options for bovine mastitis.