Laboratory of Virology and Immunology, Federal University of Federal de Pelotas, Pelotas, RS, Brazil.
Laboratory of Virology and Immunology, Federal University of Federal de Pelotas, Pelotas, RS, Brazil.
Microb Pathog. 2017 Nov;112:57-62. doi: 10.1016/j.micpath.2017.09.046. Epub 2017 Sep 21.
Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa stand out in veterinary and human medicine for their role in opportunistic infections and their pathogenic mechanisms, including the biofilms formation. It was investigated the antibacterial activity of melittin and antibiofilm of such bacteria. Twelve strains of these microorganisms isolated from bovine milk were used, as well as the strains S. aureus ATCC 12600, E. coli ATCC 8739 and Pseudomonas aeruginosa ATCC 15442. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution technique. The biofilms were formed in 96-well plates and melittin on these colonies was added at different concentrations and times. Bacteria previously exposed to melittin were evaluated for inhibition of biofilm production. The MIC and MBC were respectively in μg/mL: S. aureus (6-7 and 32-64), E. coli (40-42.5 and 64-128) and P. aeruginosa (65-70 and 64-128). S. aureus biofilms were more sensitive to the action of melittin, since upon exposure to a concentration 10 times lower than the MIC for 4 h, was completely destroyed. In Gram negative bacteria, the pre-formed biofilm was destroyed only when exposed for 4 h under the MIC. With respect to inhibition of biofilm production, S. aureus was the most sensitive again because produced only 37.2% of the biofilm formed by the control (without previous exposure to melittin), when exposed to the MIC, and at a concentration hundred times smaller than MIC, this microorganism produced 75.2% of the biofilm. E. coli was the most resistant bacteria and produced 56.3% of the biofilm, even if previously exposed to melittin MIC. Melittin presents desirable effects in combating microorganisms studied both at your disposal, biofilm destruction and inhibition of the formation, and maybe used in future studies of new strategies to combat infections caused by these pathogens.
金黄色葡萄球菌、大肠杆菌和铜绿假单胞菌在兽医和人类医学中因其在机会性感染和致病机制中的作用而引人注目，包括生物膜的形成。研究了蜂毒素对这些细菌的抗菌活性和抗生物膜作用。使用了从牛乳中分离出的 12 株这些微生物的菌株，以及金黄色葡萄球菌 ATCC 12600、大肠杆菌 ATCC 8739 和铜绿假单胞菌 ATCC 15442 菌株。采用肉汤微量稀释技术测定最小抑菌浓度（MIC）和最小杀菌浓度（MBC）。生物膜在 96 孔板中形成，在这些菌落上添加不同浓度和时间的蜂毒素。先前暴露于蜂毒素的细菌用于评估其对生物膜形成的抑制作用。MIC 和 MBC 分别以 μg/mL 表示：金黄色葡萄球菌（6-7 和 32-64）、大肠杆菌（40-42.5 和 64-128）和铜绿假单胞菌（65-70 和 64-128）。金黄色葡萄球菌生物膜对蜂毒素的作用更为敏感，因为在暴露于 MIC 浓度低 10 倍的情况下作用 4 小时，就会被完全破坏。在革兰氏阴性菌中，只有在 MIC 下暴露 4 小时才能破坏预先形成的生物膜。关于抑制生物膜的形成，金黄色葡萄球菌再次显示出最敏感的特性，因为当暴露于 MIC 时，仅产生对照（未预先暴露于蜂毒素）形成的生物膜的 37.2%，而在 MIC 浓度的 100 倍时，该微生物产生 75.2%的生物膜。大肠杆菌是最具抗性的细菌，即使先前暴露于蜂毒素 MIC，也能产生 56.3%的生物膜。蜂毒素在破坏生物膜和抑制生物膜形成方面对研究中的微生物具有理想的作用，也许可以在未来的这些病原体引起的感染防治的新策略研究中使用。
