Bacteriophage Protects Against Aerococcus viridans Infection in a Murine Mastitis Model

Abstract

Bovine mastitis, an inflammatory disease that occurs frequently in early lactation or the dry period, is primarily caused by bacterial infections. There is growing evidence that Aerococcus viridans (A. viridans) is becoming an important cause of bovine mastitis. The treatment of bovine mastitis is primarily based on antibiotics, which not only leads to a large economic burden but also the development of antibiotic resistance. On the other hand, bacteriophages present a promising alternative treatment strategy. The object of this study was to evaluate the potential of a previously isolated A. viridans phage vB_AviM_AVP (AVP) as an anti-mastitis agent in an experimental A. viridans-induced murine mastitis model. A. viridans N14 was isolated from the milk of clinical bovine mastitis and used to establish a mastitis model in mice. We demonstrated that administration of phage AVP significantly reduced colony formation by A. viridans and alleviated damage to breast tissue. In addition, reduced inflammation was indicated by decreased levels of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and myeloperoxidase (MPO) activity in the phage-treated group compared to those in the phosphate buffered saline (PBS)-treated group. To the best of our knowledge, this report is the first to show the potential use of phages as a treatment for A. viridans-induced mastitis.

The Bacteriophage vB_CbrM_HP1 Protects Crucian Carp Against Citrobacter braakii Infection

“…Compared with the control group of crucian carp, the inflammation and pathological changes were significantly alleviated in the gut and spleen tissues from crucian carp that were treated with phage. Furthermore, compared with the control group, vB_CbrM_HP1 administration resulted in a decrease in cytokine (TNF-α, IFN-γ, IL-1β) levels which was the same phenomenon as seen in the phage PIZ SAE-01E2 and the phage AVP in the treatment of infection with S. abortus equi and A. viridans, respectively (33,68). These results showed that phage vB_CbrM_HP1 can effectively alleviate lesions in vivo.…”

“…The pH and temperature stability tests were performed on the basis of a previously described method (33). vB_CbrM_HP1 with the same titer (10 10 PFU/ml) was incubated in SM buffer (pH 2-11) at 37 • C for 2 h. For the temperature stability test, vB_CbrM_HP1 with the same titer (10 10 PFU/ml) was incubated at 4 • C, 25 • C, 37 • C, 50 • C, 60 • C, 70 • C and 80 • C, and samples were taken every 20 mins to determine the phage titer.…”

Effect of NZ2114 against Streptococcus dysgalactiae biofilms and its application in murine mastitis model

“…Several researchers have reported that the 4th pair of mouse mammary gland have been used as an infection model to test the therapeutic effects of gut microbiota, probiotics and phage ( Wang et al, 2017 ; Hu et al, 2020 ; Ngassam-Tchamba et al, 2020 ). Therefore, a model of mastitis induced by S. dysgalactiae in mice was established in this work, which showed the typical symptoms of mastitis at the 4th pair of mouse mammary tissue as previously reported ( Xi et al, 2020 ), the swelling, congestion and hemorrhage mammary tissue and the increased inflammatory cytokines. Compared with the vancomycin treatment group, NZ2114 displayed significant decrease of bacteria and immunomodulatory effects against S. dysgalactiae -induced mastitis, and the effect of NZ2114 was superior to that of vancomycin.…”

Bacteriophage Therapy to Control Bovine Mastitis: A Review

“…Several phages have been identified for these purposes, but a greater proportion of work has been conducted on S. aureus being the common aetiological agent causing this infection. This approach has also been described for bacterial species such as A. viridans [ 68 ], E. coli [ 60 ] and K. oxytoca [ 9 ].…”