Bacteriophages for the treatment of mastitis in cattle

• Grant number: 22/10657-6
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• Start date: September 01, 2023
• End date: August 31, 2024
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Luciano Lopes Queiroz
• Grantee: Luciano Lopes Queiroz
• Company: Fagos Pesquisa e Desenvolvimento Ltda
• CNAE: Fabricação de medicamentos para uso veterinário
• City: São Paulo
• Associated researchers: Marcos Veiga dos Santos ; Viviani Gomes
• Associated scholarship(s): 23/13319-7 - Isolation and characterization of bacteriophages for the treatment of mastitis in dairy herds, BP.TT; 23/11003-2 - Bacteriophages for the treatment of mastitis in cattle, BP.PIPE

Abstract

The World Health Organization lists antibiotic resistance as one of the main problems of public health, food safety, and the development of new drugs. Currently, several bacterial species have multiple mechanisms of resistance to antibiotics, making it difficult to treat bacterial infections in humans and animals. The use of bacteriophages or phages - viruses that infect bacteria - as an alternative to antibiotics has gained more and more attention for medical and veterinary treatments. Brazil is the fifth-largest producer of milk and has the second-largest commercial cattle herd in the world, and the use of antibiotics in the process of creating dairy herds is extensive, which implies several additional costs for the producer and the possible appearance of bacteria resistant. The main cause of this excessive use of antibiotics is mastitis: an inflammation of the mammary gland that leads to physical and chemical changes in the milk produced, and can be caused by more than 130 different microorganisms, the main causative bacteria being Staphylococcus aureus, Staphylococcus negative coagulase, Streptococcus agalactie, Mycobacterium bovis, and Escherichia coli, (ACOSTA et al., 2016). Mastitis manifests itself in two ways, clinical and subclinical. In clinical cases, infection of the mammary glands can be diagnosed by detecting systemic symptoms and the cardinal signs of inflammation, in addition to changes in milk production, composition and/or quality. In the clinical form, the main causative agents are Staph. aureus, Strep. agalactiae and Mycoplasma spp.. In the subclinical cases, the infection is silent, not evident by systemic symptoms or localized in the mammary gland, is generally detected by alterations in milk examination tests. In subclinical cases, the main agents are Streptococcus spp. and E. Coli (TOMAZI et al., 2018). Conventional treatments of short or long duration against mastitis are carried out with the intramammary application of antibiotics. However, the use of antibiotics requires discarding the milk of the animal under treatment, increasing costs, reducing production capacity, and sometimes leading to functional loss of the mammary gland until the animal's death. Therefore, the search for new treatments is important for increasing productivity, increasing animal health and well-being, and reducing the use of antibiotics. Therefore, we propose the use of a cocktail of bacteriophages to treat of bacterial infections that cause mastitis in bovine herds. The cocktail will consist of at least six bacteriophages (phages) that will act together to eliminate the main bacteria that cause mastitis. Considering the etiology of the disease and the abundance of species isolated from cases of mastitis in Brazil, phages capable of eliminating bacteria responsible for more than 80% of cases of mastitis will be prospected (BRAGA et al., 2018), belonging to the following species: Staphylococcus aureus (0-70.3%), Streptococcus agalactiae (13-67%), Corynebacterium bovis (9.1-32%), Staphylococcus non-aureus (21-58.3%) and Escherichia coli (7-24 %) (ABEGEWI et al., 2022; AWANDKAR; KULKARNI; KHODE, 2022; ISRAEL et al., 2022; MESQUITA et al., 2019; POUTREL et al., 2018). The phages will be isolated from nature, and their morphological characteristics, stability (pH and temperature), genome, the spectrum of infection, and interaction together will be evaluated in order to select the phages with the greatest potential for the treatment of mastitis. The cocktail will be evaluated on its joint performance, then a formulation for intramammary application will be developed, which will be evaluated in relation to the efficiency of phage delivery in preclinical tests in vitro and in vivo. The chosen formulation will be evaluated for its stability in use and shelf life, and later the product will undergo clinical trials of activity and effectiveness. (AU)