Non-aureus staphylococci (NAS) are gaining importance in mastitis and public health, and some NAS have been reclassified as mammaliicocci (NASM). Bovine milk production has a major influence on the world economy, being an essential source of income for small, medium and large producers, and bovine mastitis caused by NASM can cause an economic impact. Mastitis generates financial losses due to reduced revenue, increased veterinary costs and expenses associated with animal slaughter. However, it is also a public health issue involving animal health and welfare, human health and the ecosystem. Furthermore, it is an increasingly common infection caused by NASM, including antimicrobial-resistant strains. Despite all these adverse effects that NASM can cause, some studies also point to its protective role against mastitis. Therefore, this review article addresses the negative and positive aspects that NASM can cause in bovine mastitis, the virulence of the disease and resistance factors that make it difficult to treat and, through the One Health approach, presents a holistic view of how mastitis caused by NASM can affect both animal and human health at one and the same time.

We carried out a thorough genetic evaluation ofStreptococcus dysgalactiaeisolated from clinical bovine mastitis cases and performed a phylogenetic analysis to represent the evolutionary relationship betweenS. dysgalactiaesequences. A total of 35S. dysgalactiaestrains were isolated from cases of clinical mastitis identified at a large commercial dairy farm located near Ithaca, New York. Whole-genome sequencing identified twenty-six antibiotic resistance genes, four of which were acquired genes, in addition to fifty virulence genes. Multi-locus sequence typing detected three new sequence types (STs). We conclude that a high proportion of this microorganism carries multiple virulence determinants and resistance genes, and that this indicates its potential to cause mastitis. Eight different STs were identified, of which ST453 (n= 17) was the most prevalent and ST714, ST715, ST716 were novel STs.

The isolation of non-aureus Staphylococcus (NAS) from the milk of both healthy cows and cows with mastitis has been frequently reported. However, there are few in-depth studies regarding their virulence profile and the ability of these microorganisms to form biofilms. Therefore, this research aimed to evaluate the biofilm formation capacity of NAS isolates from Brazilian milk. In this work, 309 NAS isolates were subjected to the Congo Red Agar (CRA) phenotypic test. Next, genotypic characterization was carried out by screening the bap, icaA, icaD, and MSCRAMMs genes: bbp, cna, ebps, eno, fib, fnbA, fnbB, clfA and clfB. Finally, ten isolates that presented the highest frequency of the genes analysed were selected to evaluate their ability to form biofilm on stainless-steel discs. t The number of cells (log10 CFU/cm²) in the biofilms was assessed at three time periods (24 h, 48 h, and 72 h) at a temperature of 25 °C. 35 NAS (11.32%) produced biofilms in the CRA test. Genotypic analysis showed the eno (38.5%) and bap (27.5%) genes were the most prevalent. In the analysis of biofilm formation on stainless steel, the factor 'growth time' had no significant effect on cell numbers. All selected isolates formed biofilm on stainless steel, and cell numbers were estimated to be in the 5.94 to 9.10 log10 CFU/m² range. These results provide evidence that NAS isolated from milk may represent a risk to human and animal health since they carry several virulence genes and demonstrate the ability to form biofilms.

The consumer demand for a reduction in the use of synthetic additives in food has been providing a greater search and incentive for the food industries to use new alternatives for food preservation. Among them, there is the initiative to use essential oils (EOs) due to their antimicrobial properties, coming from specific compounds in their compositions. However, in view of limitations related to the use of EOs, as well as their susceptibility to oxidation and degradation, the possibility arises of employing protection methods such as microencapsulation to minimize the impairment of the benefits associated with the application of EOs. This study aimed to examine the antimicrobial effect of turmeric and nutmeg EOs against microbial strains of Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella spp., as well as the microparticles of the EOs involved. Analyses of the minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC), and the developed microparticles, as well as the verification of the synergistic inhibitory action between these oils, were carried out. For free oils, antimicrobial action was evidenced against the vast majority of microorganisms tested, with free nutmeg EO having a better antimicrobial effect than free turmeric oil. In contrast, for encapsulated oils, only antimicrobial action was noted against strains of Listeria. Furthermore, the synergism of free oils did not potentiate the antimicrobial action. Regarding the alternative of microencapsulation of EOs, it was obtained that the results in which chitosan was used as wall material were more promising than when gelatin was used as wall material.