Yahya Mohd Fakharul Zaman Raja, Alias Zazali, Karsani Saiful Anuar
Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
Faculty of Applied Sciences, Universiti Teknologi MARA Shah Alam, 40450, Shah Alam, Malaysia.
Folia Microbiol (Praha). 2018 Jan;63(1):23-30. doi: 10.1007/s12223-017-0532-9. Epub 2017 May 24.
Biofilms are complex microbial communities that tend to attach to either biotic or abiotic surface. Enclosed in a self-produced extracellular polymeric substance (EPS) matrix, the biofilms often cause persistent infections. The objective of this study was to investigate the antibiofilm activity of dimethyl sulfoxide (DMSO) and afatinib against Gram-negative pathogens. Test microorganisms used in this study were Escherichia coli ATCC 1299, Pseudomonas aeruginosa ATCC 10145, and Salmonella typhimurium ATCC 14028. Biofilms were developed in 96-well microplate at 37°C for 24 h. Following removal of non-adherent cells, analysis of biofilm viability, biofilm biomass, and extracellular polymeric substances (EPS) matrix were performed using resazurin assay, crystal violet assay, and attenuated total reflectance fourier transform infrared (ATR-FTIR) spectroscopy, respectively. Bradford protein assay was conducted to determine the total amount of EPS proteins. The results demonstrated that both 32% DMSO alone and its combination with 3.2 μg/mL afatinib were effective in killing biofilm cells and reducing biofilm biomass. IR spectral variations of EPS matrix of biofilms in the range between 1700 and 900 cm were also observed. Reduction in EPS proteins verified the chemical modifications of EPS matrix. In conclusion, 32% DMSO alone and its combination with 3.2 μg/mL afatinib showed remarkable antibiofilm activities against Gram-negative pathogens. It was suggested that the biofilm inhibition was mediated by the chemical modification of EPS matrix.
生物膜是倾向于附着在生物或非生物表面的复杂微生物群落。生物膜被包裹在自身产生的细胞外聚合物（EPS）基质中，常常会引发持续性感染。本研究的目的是调查二甲基亚砜（DMSO）和阿法替尼对革兰氏阴性病原体的抗生物膜活性。本研究中使用的测试微生物为大肠埃希菌ATCC 1299、铜绿假单胞菌ATCC 10145和鼠伤寒沙门氏菌ATCC 14028。生物膜在96孔微孔板中于37°C培养24小时。去除未附着细胞后，分别使用刃天青测定法、结晶紫测定法和衰减全反射傅里叶变换红外（ATR-FTIR）光谱法对生物膜活力、生物膜生物量和细胞外聚合物（EPS）基质进行分析。进行Bradford蛋白质测定以确定EPS蛋白质的总量。结果表明，单独使用32% DMSO及其与3.2 μg/mL阿法替尼的组合在杀死生物膜细胞和减少生物膜生物量方面均有效。还观察到生物膜EPS基质在1700至900 cm范围内的红外光谱变化。EPS蛋白质的减少证实了EPS基质的化学修饰。总之，单独使用32% DMSO及其与3.2 μg/mL阿法替尼的组合对革兰氏阴性病原体显示出显著的抗生物膜活性。提示生物膜抑制是由EPS基质的化学修饰介导的。
