Group of Applied Medical Microbiology - GrAMM, Postgraduate Program in Medical Microbiology, School of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil; Biomedicine School, Christus University, Fortaleza, CE, Brazil; Department of Morphology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil.
Group of Applied Medical Microbiology - GrAMM, Postgraduate Program in Medical Microbiology, School of Medicine, Federal University of Ceara, Fortaleza, CE, Brazil.
Anaerobe. 2021 Jun;69:102322. doi: 10.1016/j.anaerobe.2021.102322. Epub 2021 Jan 27.
Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacillus which is the leading cause of health-care-associated infective diarrhea. The rising incidence of antibiotic resistance in pathogens such as C. difficile makes researches on alternative antibacterial products very important, especially those exploring natural products like propolis. Brazilian Red Propolis, found in the Northeast region of Brazil, is composed by products from regional plants that have the antimicrobial properties. This study aimed to evaluate the in vitro activity of Brazilian Red Propolis (BRP) against C. difficile strains in planktonic and biofilm forms. The susceptibility of four strains of C. difficile to BRP was analyzed by broth microdilution method and vancomycin was included as control drug. BRP-exposed C. difficile cells were evaluated by scanning electron microscopy (SEM). Then, the effects of BRP on growing and mature C. difficile biofilms were also evaluated. BRP minimum inhibitory concentration was 625 μg/mL against all tested strains, while vancomycin MIC range was 0.5-2 μg/mL. SEM showed the loss of homogeneity in bacterial cell wall and cell fragmentation, after BRP-exposure. BRP, at MIC, reduced (P < 0.05) the biomass, matrix proteins and matrix carbohydrates of growing biofilms, and, at 8xMIC, reduced (P < 0.05) the biomass and matrix proteins of mature biofilms. The present study demonstrated that BRP inhibits planktonic growth, damages cell wall, decreases biofilm growth and harms mature biofilms of C. difficile.
艰难梭菌是一种革兰氏阳性、产芽孢、厌氧杆菌，是导致医疗保健相关感染性腹泻的主要原因。由于病原体如艰难梭菌对抗生素的耐药性不断上升，因此对替代抗菌产品的研究非常重要，特别是那些探索天然产物如蜂胶的研究。巴西红蜂胶存在于巴西东北部地区，由具有抗菌特性的当地植物产品组成。本研究旨在评估巴西红蜂胶（BRP）对浮游和生物膜形式艰难梭菌菌株的体外活性。采用肉汤微量稀释法分析了 4 株艰难梭菌对 BRP 的敏感性，并将万古霉素作为对照药物。通过扫描电子显微镜（SEM）评估 BRP 暴露后的艰难梭菌细胞。然后，还评估了 BRP 对生长中和成熟的艰难梭菌生物膜的影响。BRP 对所有测试菌株的最小抑菌浓度（MIC）为 625μg/mL，而万古霉素的 MIC 范围为 0.5-2μg/mL。SEM 显示，BRP 暴露后细菌细胞壁失去均匀性，出现细胞碎片化。BRP 在 MIC 时减少了生长生物膜的生物量、基质蛋白和基质碳水化合物（P<0.05），在 8xMIC 时减少了成熟生物膜的生物量和基质蛋白（P<0.05）。本研究表明，BRP 可抑制浮游生长、破坏细胞壁、减少生物膜生长并损害艰难梭菌的成熟生物膜。
