| Congresso Brasileiro de Microbiologia 2023 | Resumo: 410-2 | ||||
Resumo:Mastitis, an inflammatory condition affecting dairy cows, presents critical health and economic challenges due to chronic mastitis development and antibiotic resistance driven by biofilms. To address these issues, this study evaluated the impact of an antibiotic-free combinatorial therapy on well-established biofilms formed by mastitis-causing pathogens, including Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Staphylococcus chromogenes. Forty-five mastitis isolates were assessed for biofilm-forming capacity using the crystal violet assay in 0.4% glucose-supplemented BHI media at 37°C for 48 hours, with an initial inoculum of 105 cells.ml-1. The most proficient biofilm producers for each species were selected as targets. Biofilms were established in sterile 96-well flat-bottomed plastic tissue culture, followed by exposure to antimicrobials either individually (at minimal inhibitory concentration values) or in combination (a 4- and 16-fold reduction for AMP_1 and CA_3, respectively, compared to individual). Biofilm were challenged for 24 hours. The residual biofilm was quantified using the violet crystal method. Statistical analysis, including the Shapiro-Wilk test for normality and the Kruskal-Wallis Test for significant differences, with Dunn's Test for pairwise multiple comparisons, was performed on the collected data. Among the tested strains, two strains each of E. coli, K. pneumoniae, S. aureus, and one strain of S. chromogenes demonstrated the highest biofilm-forming capability and were selected as representative targets of Gram-positive and Gram-negative groups, as well as clinical and environmental mastitis pathogens. AMP_1, at its full dosage, effectively reduced the established biofilms for all seven strains (p < 0.05), reaching a 3-fold reduction in biofilm remains, from average 0.56 to 0.18 nm. However, the dose-reduced combination showed no significant decrease in biofilm reduction. Nonetheless, CA_3 alone exhibited a significant reduction in biofilms for both K. pneumoniae strains, while its effectiveness against the other species was comparatively lower. These findings underscore AMP_1's potential as a potent alternative for mastitis treatment, offering promising prospects in combating this condition. Future experiments will focus on devising delivery systems to evaluate the efficacy of these molecules in vivo and their potential implications for addressing mastitis-related challenges in the dairy industry. Palavras-chave: antimicrobial peptide, bovine mastitis, combinatorial therapy, biofilm disruption Agência de fomento:DAIRY INNOVATION HUB, FAPEMIG, CAPES, CNPq | |||||