Gabriel Michelutti Do Nascimento

Pre- and post-milking teat antisepsis is one of the most effective methods for reducing the incidence of mastitis. Plant extracts have proven effective in reducing microorganisms, providing a natural alternative for antisepsis, along with additional benefits for teat health. This study aimed to evaluate the antimicrobial and antiseptic effects of two newly formulated products, used as pre-dipping and post-dipping agents, respectively, based on plant extracts from papain (Carica papaya), aloe vera (Aloe barbadensis), andiroba (Carapa guianensis), copaiba (Copaifera officinalis), tea tree (Melaleuca alternifolia), and barbatimão (Stryphnodendron barbatiman). Minimum inhibitory concentration tests were performed in vitro, along with microbiological analyses of different bacterial groups and in vivo compliance assessments to evaluate the antimicrobial activity of the formulations, as well as the molecular identification of Staphylococcus aureus. The results demonstrated that the products were effective in vitro against the main pathogens that cause mastitis, including Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli. In the in vivo assays, similar performance was observed between the tested products and the control products, indicating that the plant-extract-based formulations, applied as pre-dipping and post-dipping agents, effectively reduced the microbial load on the teats. The effects were equivalent to those of hydrogen-peroxide- and iodine-based products, being able to reduce the total microbial load by more than 80%.

Bovine mastitis is one of the main causes of economic damage in dairy farms. Therefore, the control and prevention of microorganisms involved in this disease, mainly Escherichia coli, Staphylococcus aureus, and Streptococcus agalactiae, are essential. One of the most important steps for the prevention of the disease is the use of antiseptic products before and after the milking process to avoid bacteria from infecting the udder of the animal. Currently, the most used antiseptic product in dairy farms is iodine-based, and organic dairy farms, which follow several strict regulations, including the use of natural products whenever possible, are often forced to adopt non-natural antiseptic products, such as iodine-based ones, because of the lack of natural alternatives. Propolis, a natural substance produced by honeybees, has been extensively studied for its various properties, one of which is antimicrobial activity. Therefore, a new natural antiseptic product containing 1% propolis in 10% hydroalcoholic solution for the pre-dipping, and 10% glycerol solution added with 0.2% citronella oil for the post-dipping was analyzed for its capacity to reduce bacteria in vivo in order to prevent bovine mastitis, allowing its use on organic dairy farms. A total of 128 samples were analyzed in terms of bacterial growth for Enterobacteriaceae and Staphylococcus spp. using the spreadplate technique. The reduction in the bacterial concentration after the application of the products was compared between two antiseptic solutions, an iodine-based solution as the control and a propolis-based one as the natural alternative. The results obtained show a similar efficiency for both products in terms of total bacterial reduction, indicating considerable antimicrobial activity against bacteria most commonly associated with bovine mastitis. Molecular analysis was carried out for the identification of Streptococcus agalactiae; the PCR results were negative for the presence of S. agalactiae in all samples, indicating that the animals most likely did not have any form of the disease. The efficiency of the natural antiseptic was satisfactory, indicating an important find facilitating organic milk production worldwide, showcasing a natural antiseptic solution with efficient antimicrobial activity.

Neonatal diarrhea is amongst the most frequent diseases affecting calves, leading to damages in milk production. Although Escherichia coli is a commensal microorganism in the gastrointestinal tract, some pathotypes are known to cause high prevalence of diarrhea and food poisoning. The rapidly increasing resistance of bacteria to antimicrobials leads to the research in new, alternative treatment options. The present study aimed at the detection of E. coli pathotypes in newborn diarrheic and non-diarrheic calves, as well as susceptibility tests for antimicrobials and vegetal extracts. Samples were collected from animals located in dairy farms in the state of Minas Gerais, Brazil. The samples were sent for microbiological isolation, genetic identification using PCR and antimicrobial tests. A total of 35 strains from diarrheic animals tested positive for at least one of the virulence genes analyzed: stx1, stx2, eae, bfp and sta. As for the non-diarrheic animals, 9 isolated strains possessed one of or both stx1 and stx2 genes, classifying these non-diarrheic cattle as reservoirs for the STEC pathotype and possible biological vectors of this pathogen. Regarding the susceptibility tests, most isolates displayed resistance to multiple antimicrobial classes. Among the vegetal extracts tested, all isolates tested sensitive to the active ingredient of Salvia officinalis L. (sage). Showcasing an alternative tool to aid in the treatment of pathogenic bacteria.