Feng Jinsong, Lamour Guillaume, Xue Rui, Mirvakliki Mehr Negar, Hatzikiriakos Savvas G, Xu Jie, Li Hongbin, Wang Shuo, Lu Xiaonan
Food, Nutrition, and Health Program, Faculty of Land and Food Systems, The University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
Int J Food Microbiol. 2016 Dec 5;238:172-182. doi: 10.1016/j.ijfoodmicro.2016.09.008. Epub 2016 Sep 13.
Campylobacter jejuni is a microaerophilic pathogen and leading cause of human gastroenteritis. The presence of C. jejuni encased in biofilms found in meat and poultry processing facilities may be the major strategy for its survival and dissemination in aerobic environment. In this study, Staphylococcus aureus, Salmonella enterica, or Pseudomonas aeruginosa was mixed with C. jejuni F38011 as a culture to form dual-species biofilms. After 4days' exposure to aerobic stress, no viable C. jejuni cells could be detected from mono-species C. jejuni biofilm. In contrast, at least 4.7logCFU/cm of viable C. jejuni cells existed in some dual-species biofilms. To elucidate the mechanism of protection mode, chemical, physical and morphological features of biofilms were characterized. Dual-species biofilms contained a higher level of extracellular polymeric substances with a more diversified chemical composition, especially for polysaccharides and proteins, than mono-species C. jejuni biofilm. Structure of dual-species biofilms was more compact and their surface was >8 times smoother than mono-species C. jejuni biofilm, as indicated by atomic force microscopy. Under desiccation stress, water content of dual-species biofilms decreased slowly and remained at higher levels for a longer time than mono-species C. jejuni biofilm. The surface of all biofilms was hydrophilic, but total surface energy of dual-species biofilms (ranging from 52.5 to 56.2mJ/m) was lower than that of mono-species C. jejuni biofilm, leading to more resistance to wetting by polar liquids. This knowledge can aid in developing intervention strategies to decrease the survival and dispersal of C. jejuni into foods or environment.
空肠弯曲菌是一种微需氧病原体,也是人类肠胃炎的主要病因。在肉类和家禽加工设施中发现的包裹在生物膜中的空肠弯曲菌,可能是其在有氧环境中生存和传播的主要策略。在本研究中,将金黄色葡萄球菌、肠炎沙门氏菌或铜绿假单胞菌与空肠弯曲菌F38011混合培养以形成双物种生物膜。在有氧应激暴露4天后,从单物种空肠弯曲菌生物膜中未检测到存活的空肠弯曲菌细胞。相比之下,在一些双物种生物膜中存在至少4.7logCFU/cm的存活空肠弯曲菌细胞。为了阐明保护模式的机制,对生物膜的化学、物理和形态特征进行了表征。与单物种空肠弯曲菌生物膜相比,双物种生物膜含有更高水平的细胞外聚合物,其化学成分更加多样化,尤其是多糖和蛋白质。原子力显微镜显示,双物种生物膜的结构更紧凑,其表面比单物种空肠弯曲菌生物膜光滑8倍以上。在干燥应激下,双物种生物膜的水分含量下降缓慢,并且比单物种空肠弯曲菌生物膜在更长时间内保持在较高水平。所有生物膜的表面都是亲水的,但双物种生物膜的总表面能(范围为52.5至56.2mJ/m)低于单物种空肠弯曲菌生物膜,导致对极性液体的润湿性更具抵抗力。这些知识有助于制定干预策略,以减少空肠弯曲菌在食品或环境中的存活和扩散。