Recent progress in antibiofilm strategies in the dairy industry

Biofilm formation allows microorganisms including bacteria to persist on abiotic or biotic surfaces, to resist treatments with biocides (disinfectants and antibiotics) and to evade the immune response in animal hosts much more than they do in the planktonic form. Bacteria able to form biofilm can be troublesome in the dairy industry, both by causing clinical symptoms in livestock and by colonizing milking devices and milk processing equipment, resulting in dairy products of lower quality and sometimes raising serious food safety issues. In fact, most of the bacterial species isolated frequently in the dairy chain have the ability to form biofilm. Common examples include Staphylococcus aureus and other staphylococci that frequently infect mammary glands, but also Bacillus spp., Listeria monocytogenes and Pseudomonas spp. which cause spoilage of dairy products and sometimes foodborne illnesses. The economic losses due to biofilm formation in the dairy industry are considerable, and scientists are constantly solicited to develop new antibiofilm strategies, especially using biocides of natural origin. Although the number of studies in this subject area has exploded in recent years, the in vivo efficacy of most novel approaches remains to be explored. Used alone or to increase the efficacy of disinfectants or antibiotics, they could allow the implementation of strategies having less impact on the environment. Their use is expected to lead to less reliance on antibiotics to treat intramammary infections in dairy farms and to the use of lower concentrations of chemical disinfectants in dairy processing plants.

Dietary anti-inflammatory and anti-bacterial medicinal plants and its compounds in bovine mastitis associated impact on human life

Bovine mastitis (BM) is the most common bacterial mediated inflammatory disease in the dairy cattle that causes huge economic loss to the dairy industry due to decreased milk quality and quantity. Milk is the essential food in the human diet, and rich in crucial nutrients that helps in lowering the risk of diseases like hypertension, cardiovascular diseases and type 2 diabetes. The main causative agents of the disease include various gram negative, and positive bacteria, along with other risk factors such as udder shape, age, genetic, and environmental factors also contributes much for the disease. Currently, antibiotics, immunotherapy, probiotics, dry cow, and lactation therapy are commonly recommended for BM. However, these treatments can only decrease the rise of new cases but can't eliminate the causative agents, and they also exhibit several limitations. Hence, there is an urgent need of a potential source that can generate a typical and ideal treatment to overcome the limitations and eliminate the pathogens. Among the various sources, medicinal plants and its derived products always play a significant role in drug discovery against several diseases. In addition, they are also known for its low toxicity and minimum resistance features. Therefore, plants and its compounds that possess anti-inflammatory and anti-bacterial properties can serve better in bovine mastitis. In addition, the plants that are serving as a food source and possessing pharmacological properties can act even better in bovine mastitis. Hence, in this evidence-based study, we particularly review the dietary medicinal plants and derived products that are proven for anti-inflammatory and anti-bacterial effects. Moreover, the role of each dietary plant and its compounds along with possible role in the management of bovine mastitis are delineated. In this way, this article serves as a standalone source for the researchers working in this area to help in the management of BM.

Effects of Tea Tree Oil on Production Performance, Serum Parameter Indices, and Immunity in Postpartum Dairy Cows

Tea tree oil (TTO) plays an important role in regulating lipid metabolism and has anti-inflammatory properties. In postpartum dairy cows, dry matter intake (DMI) is dramatically decreased, resulting in lipid metabolism disorder and the systemic pro-inflammatory response. However, the effects of TTO on glucolipid metabolism and immunity in postpartum dairy cows remain uninvestigated. Therefore, this study aimed to evaluate the effects of TTO on production performance, serum biochemical indicators, and immunity in postpartum dairy cows. Our results demonstrate that DMI tended to increase (p = 0.07) in the total mixed ration (TMR) diets supplemented with 0.01% TTO/dry matter (DM) basis relative to that in the control group. The 4% fat-corrected milk (FCM) content in the 0.01% and 0.02% TTO groups showed an increase (p = 0.09) compared with that in the control. Remarkably, the levels of globulin (GLO) and immunoglobulin G (IgG) were elevated (p < 0.05) in the TMR diet supplemented with 0.02% TTO compared to those in the control group. The TTO caused no profound changes in cholesterol (CHO), triglyceride (TG), high-density lipoprotein (HDL), or low-density lipoprotein (LDL). Notably, 0.02% TTO increased (p < 0.05) the serum glucose concentration relative to that in the control group. In conclusion, our results demonstrate that TTO could improve glucolipid metabolism and enhance immunity in postpartum dairy cows. It may be a novel resolution strategy for body condition recovery and the improvement of milk performance.

Differences between the global transcriptomes of Salmonella enterica serovars Dublin and Cerro infecting bovine epithelial cells

Background

The impact of S. enterica colonization in cattle is highly variable and often serovar-dependent. The aim of this study was to compare the global transcriptomes of highly pathogenic bovine-adapted S. enterica serovar Dublin and the less pathogenic, bovine-adapted, serovar Cerro during interactions with bovine epithelial cells, to identify genes that impact serovar-related outcomes of S. enterica infections in dairy animals.

Result

Bovine epithelial cells were infected with S. enterica strains from serovars Dublin and Cerro, and the bacterial RNA was extracted and sequenced. The total number of paired-end reads uniquely mapped to non-rRNA and non-tRNA genes in the reference genomes ranged between 12.1 M (Million) and 23.4 M (median: 15.7 M). In total, 360 differentially expressed genes (DEGs) were identified with at least two-fold differences in the transcript abundances between S. Dublin and S. Cerro (false discovery rate ≤ 5%). The highest number of DEGs (17.5%, 63 of 360 genes) between the two serovars were located on the genomic regions potentially associated with Salmonella Pathogenicity Islands (SPIs). DEGs potentially located in the SPI-regions that were upregulated (≥ 2-fold) in the S. Dublin compared with S. Cerro included: 37 SPI-1 genes encoding mostly Type 3 Secretion System (T3SS) apparatus and effectors; all of the six SPI-4 genes encoding type I secretion apparatus (siiABCDEF); T3SS effectors and chaperone (sopB, pipB, and sigE) located in SPI-5; type VI secretion system associated protein coding genes (sciJKNOR) located in SPI-6; and T3SS effector sopF in SPI-11. Additional major functional categories of DEGs included transcription regulators (n = 25), amino acid transport and metabolism (n = 20), carbohydrate transport and metabolism (n = 20), energy production and metabolism (n = 19), cell membrane biogenesis (n = 18), and coenzyme transport and metabolism (n = 15). DEGs were further mapped to the metabolic pathways listed in the KEGG database; most genes of the fatty acid β-oxidation pathway were upregulated/uniquely present in the S. Dublin strains compared with the S. Cerro strains.

Conclusions

This study identified S. enterica genes that may be responsible for symptomatic or asymptomatic infection and colonization of two bovine-adapted serovars in cattle.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08725-z.

The protective roles of tea tree oil extracts in bovine mammary epithelial cells and polymorphonuclear leukocytes

Background

Tea tree oil (TTO) plays an important role in antibacterial activity and alleviating the inflammatory responses. Bovine mammary epithelium and polymorphonuclear leukocytes (PMNL) can actively respond to bovine mastitis infection. However, regulatory effects of TTO extracts on the innate immune response of bovine mammary epithelial cells (BMECs) and PMNL remain not reported. Therefore, aim of the study was to evaluate the effects of TTO extracts on the mRNA levels of the genes involved in the innate immune response of BMECs and PMNL.

Results

Our results demonstrated that addition of 0.025% and 0.05% TTO increased the proliferation of BMECs, and significantly enhanced (P < 0.05) the viability of BMECs exposed to Staphylococcus aureus (S. aureus). An inhibitory effect was observed against the growth of S. aureus by TTO incubation. The 0.05% TTO reduced S. aureus biofilm formation, association and invasion of S. aureus to BMECs, and changed the morphological and structural features of S. aureus. The proinflammatory cytokines IL-1β, IL-6, and TNF-α were decreased (P < 0.001) by the incubation of TTO. Interestingly, the expression of IL-8 known for PMNL chemotactic function was elevated (P < 0.05) by 0.05% TTO treatment. Consistently, 0.05% TTO increased the migration of PMNL in S. aureus-exposed BMECs when compared with S. aureus treatment alone (P < 0.05). In addition, PMNL incubated with 0.05% TTO decreased the levels of NFKB inhibitor alpha (NFKBIA) and TNF-α.

Conclusions

Our results indicate that use of TTO can relieve the BMECs pro-inflammatory response caused by S. aureus and promote the migration of PMNL to mount the innate immune responses, and it may be novel strategy for the treatment of bovine mastitis caused by S. aureus.

Bovine mastitis: risk factors, therapeutic strategies, and alternative treatments - A review

Bovine mastitis, an inflammation of the mammary gland, is the most common disease of dairy cattle causing economic losses due to reduced yield and poor quality of milk. The etiological agents include a variety of gram-positive and gram-negative bacteria, and can be either contagious (e.g., Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma spp.) or environmental (e.g., Escherichia coli, Enterococcus spp., coagulase-negative Staphylococcus, Streptococcus uberis). Improving sanitation such as enhanced milking hygiene, implementation of post-milking teat disinfection, maintenance of milking machines are general measures to prevent new cases of mastitis, but treatment of active mastitis infection is dependant mainly on antibiotics. However, the extensive use of antibiotics increased concerns about emergence of antibiotic-resistant pathogens and that led the dairy industries to reduce the use of antibiotics. Therefore, alternative therapies for prevention and treatment of bovine mastitis, particularly natural products from plants and animals, have been sought. This review provides an overview of bovine mastitis in the aspects of risk factors, control and treatments, and emerging therapeutic alternatives in the control of bovine mastitis.

Interaction of Salmonella enterica with Bovine Epithelial Cells Demonstrates Serovar-Specific Association and Invasion Patterns

Dairy cows are known reservoirs of Salmonella enterica and human salmonellosis has been attributed to the consumption of contaminated dairy and beef products as well as poultry meat and eggs. Although many S. enterica serovars are known to colonize the gastrointestinal tract of cattle, the interactions between dairy commensal (or persistent) and transient Salmonella serovars with bovine epithelial cells are not well understood. Association-invasion assays were used to characterize the interactions of 26 S. enterica strains from bovine origins, comprising serovars Anatum, Cerro, Dublin, Give, Kentucky, Mbandaka, Meleagridis, Montevideo, Muenster, Newport, Oranienburg, Senftenberg, and Typhimurium, with cultured bovine epithelial cells. There were significant differences in the association with and invasion of bovine epithelial cells within and across Salmonella serovars (Tukey's Honestly Significant Difference test, p < 0.05). Salmonella enterica serovar Dublin strains were the most invasive, whereas Kentucky, Mbandaka, Cerro, and Give strains were the least invasive (p < 0.05). Significant differences in motility on semisolid medium were also observed between strains from different serovars. Findings from this study demonstrate an underappreciated level of phenotypic diversity among Salmonella strains within and across serovars and serve as a baseline for future studies that may identify the molecular mechanisms of asymptomatic Salmonella carriage and bovine salmonellosis.

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

Mastitis is among the most common and challenging diseases of dairy animals. It is an inflammation of udder tissues due to physical damage, chemical irritation, or infection caused by certain pathogens. Bovine mastitis has been known for ages, but its complex etiology and multi-factorial nature make it difficult to control. Mastitis may have a negative impact on human health by inducing antibiotic-resistant pathogens that may spread, which is threatening. Researchers are continuously struggling to devise suitable methods for mastitis control. Management strategies are mainly focused on disease prevention by farm management which includes proper hygiene, trained staff to monitor minor changes in the udder or milk, and better diagnostic and treatment methods. New technologies which have the potential to unravel this complicated disease include improved diagnostic tools, based on advanced genomics or proteomics, prevention, based on vaccines and immune modulators, and metabolic products of probiotics such as bacteriocins and gene therapy.

Sensitizing of β-lactam resistance by tannic acid in methicillin-resistant S. aureus

Methicillin-resistant Staphylococcus aureus (MRSA) infections treatment of which is hard and failed, due to being resistant to all types of β-lactams, have been emerged in hospitals and community. Long-term usage of antibiotics and over doses of antibiotics used in the treatment of infections cause bacteria to develop resistance to antibiotics. β-lactams combined with tannic acid can be a good alternative to sensitize the resistance of β-lactams used in the treatment of MRSA, due to their synergistic activities. In this study, after minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of sole tannic acid and β-lactam were investigated for each isolate, the synergistic activities of β-lactams combined with tannic acid against one MRSA ATCC 43300 and four MRSA clinical isolates were investigated with the concentrations starting at four fold of MICs of sole treatments of tannic acid and β-lactam by using checkerboard assay. To investigate sole and combination activities of tannic acid and β-lactams, MIC and MBCs were observed. Results of this study showed that the activities of β-lactams combined with tannic acid were synergistic and partially synergistic against MRSA isolates with FIC indexes ranged from 0.174 to 0.477 and 0.562 to 0.850, respectively. MIC of β-lactams were decreased 2-16 fold by sub-inhibitory concentrations of tannic acid without toxicity. Alternative treatment options of natural compounds such as tannic acid and β-lactams must be investigated further and developed to overcome the emergence of β-lactam resistance and treat MRSA infections by sensitizing the resistance of β-lactams.

The protective effect of chlorogenic acid on bovine mammary epithelial cells and neutrophil function

Chlorogenic acid (CGA) is the ester of caffeic acid and quinic acid and plays an important role in antibacterial activity and anti-inflammatory properties. The objective of this study was to examine the effects of CGA on the growth of Staphylococcus aureus and the mRNA levels of the genes encoding the inflammatory response cytokines, κ-casein, and neutrophil function in bovine mammary epithelial cells (BMEC) exposed to S. aureus. Chlorogenic acid has important antibacterial, antioxidant, and anti-inflammatory functions; however, the effect of CGA on BMEC and neutrophils exposed to S. aureus has not been investigated previously. Our results demonstrated that 10, 20, and 30 μg/mL CGA had no cytotoxic effects on BMEC in culture, and that 20 μg/mL CGA enhanced the viability of BMEC exposed to S. aureus, whereas 30 μg/mL CGA reduced S. aureus growth after 9 h compared with controls. The rate of S. aureus invasion into BMEC was also attenuated by 30 μg/mL CGA compared with controls, whereas this treatment led to reduced abundance of IL6, IL8, and TLR2 mRNA in S. aureus-exposed BMEC. Migration of bovine polymorphonuclear leukocytes was significantly decreased in S. aureus-exposed BMEC with 10 and 20 μg/mL CGA treatment when compared with S. aureus treatment alone. In addition, incubation with 20 or 30 μg/mL CGA enhanced the phagocytic ability of polymorphonuclear leukocytes compared with the control group. Importantly, levels of κ-casein were enhanced by treatment of S. aureus-exposed BMEC with CGA. Our results suggest that the use of CGA may be a potent therapeutic tool against bovine mastitis caused by S. aureus.

A T4virus prevents biofilm formation by Trueperella pyogenes

Trueperella pyogenes is an opportunistic pathogen of many animal species. It causes economic losses worldwide, through mastitis, metritis and mainly endometritis in dairy cows. The ability of this bacterium to form biofilms is implicated in chronic infections through hampering immune system recognition and antibiotic penetration. Since it is difficult to eradicate T. pyogenes infections with antibiotics, phage therapy presents itself as a non-toxic, effective and economically viable alternative. The present study evaluated the use of the bacteriophage vB_EcoM-UFV13 (UFV13) in the prevention of T. pyogenes biofilm development. Based upon two different approaches (crystal violet and sessile cell counting) we observed that only a multiplicity of infection (MOI) of 10 showed a statistically significant reduction in biofilm formation. Although the exact mechanisms of biofilm disruption and cell-adhesion inhibition have not been determined, genome sequence analysis of the Escherichia phage UFV13 revealed a repertoire of virion-associated peptidoglycan hydrolases (VAPGHs). The present study presents new findings regarding the disruption of biofilm formation of a Gram-positive bacterium. Subsequent transcriptomic and proteomic research will help us to understand the exact interaction mechanisms between UFV13 and T. pyogenes.

Eradication and Sensitization of Methicillin Resistant Staphylococcus aureus to Methicillin with Bioactive Extracts of Berry Pomace

The therapeutic roles of phenolic blueberry (Vaccinium corymbosum) and blackberry (Rubus fruticosus) pomace (commercial byproduct) extracts (BPE) and their mechanism of actions were evaluated against methicillin resistant Staphylococcus aureus (MRSA). Five major phenolic acids of BPE, e.g., protocatechuic, p. coumaric, vanillic, caffeic, and gallic acids, as well as crude BPE completely inhibited the growth of vegetative MRSA in vitro while BPE+methicillin significantly reduced MRSA biofilm formation on plastic surface. In addition, BPE restored the effectiveness of methicillin against MRSA by down-regulating the expression of methicillin resistance (mecA) and efflux pump (norA, norB, norC, mdeA, sdrM, and sepA) genes. Antibiogram with broth microdilution method showed that MIC of methicillin reduced from 512 μg/mL to 4 μg/mL when combined with only 200 μg Gallic Acid Equivalent (GAE)/mL of BPE. Significant reduction in MRSA adherence to and invasion into human skin keratinocyte Hek001 cells were also noticed in the presence of BPE. BPE induced anti-apoptosis and anti-autophagy pathways through overexpression of Bcl-2 gene and down-regulation of TRADD and Bax genes (inducers of apoptosis pathway) in Hek001 cells. In summary, novel and sustainable prophylactic therapy can be developed with BPE in combination with currently available antibiotics, especially methicillin, against skin and soft tissue infections with MRSA.

Complete Genome Sequence of vB_EcoM-UFV13, a New Bacteriophage Able To Disrupt Trueperella pyogenes Biofilm

vB_EcoM-UFV13, a member of the T4virus genus, shows lytic activity against Escherichia coli and effectiveness in controlling the biofilm formed by Trueperella pyogenes, which qualifies it as a promising component of phage cocktails for mastitis and metritis control.