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Abstract：
A polymicrobial biofilm model of Komagataeibacter hansenii and Pseudomonas aeruginosa was developed to understand whether a pre-existing matrix affects the ability of another species to build a biofilm. P. aeruginosa was inoculated onto the preformed K. hansenii biofilm consisting of a cellulose matrix. P. aeruginosa PAO1 colonized and infiltrated the K. hansenii bacterial cellulose biofilm (BC), as indicated by the presence of cells at 19 μm depth in the translucent hydrogel matrix. Bacterial cell density increased along the imaged depth of the biofilm (17-19 μm). On day 5, the average bacterial count across sections was 67 ± 4 % P. aeruginosa PAO1 and 33 ± 6 % K. hansenii. Biophysical characterization of the biofilm indicated that colonization by P. aeruginosa modified the biophysical properties of the BC matrix, which inlcuded increased density, heterogeneity, degradation temperature and thermal stability, and reduced crystallinity, swelling ability and moisture content. This further indicates colonization of the biofilm by P. aeruginosa. While eDNA fibres - a key viscoelastic component of P. aeruginosa biofilm - were present on the surface of the co-cultured biofilm on day 1, their abundance decreased over time, and by day 5, no eDNA was observed, either on the surface or within the matrix. P. aeruginosa-colonized biofilm devoid of eDNA retained its mechanical properties. The observations demonstrate that a pre-existing biofilm scaffold of K. hansenii inhibits P. aeruginosa PAO1 eDNA production and suggest that eDNA production is a response by P. aeruginosa to the viscoelastic properties of its environment.
摘要：
开发了Komagataeibacterhansenii和铜绿假单胞菌的多微生物生物膜模型，以了解预先存在的基质是否会影响另一个物种构建生物膜的能力。将铜绿假单胞菌接种到由纤维素基质组成的预先形成的K.hansenii生物膜上。铜绿假单胞菌PAO1定植并浸润了K.hansenii细菌纤维素生物膜（BC），如半透明水凝胶基质中19μm深度的细胞的存在所指示的。细菌细胞密度沿生物膜的成像深度（17-19μm）增加。在第5天,跨切片的平均细菌计数为67±4%铜绿假单胞菌PAO1和33±6%K.hansenii。生物膜的生物物理表征表明，铜绿假单胞菌的定植改变了BC基质的生物物理特性，增加了密度，异质性，降解温度和热稳定性，和降低结晶度，溶胀能力和水分含量。这进一步表明生物膜被铜绿假单胞菌定殖。虽然eDNA纤维-铜绿假单胞菌生物膜的关键粘弹性成分-在第1天存在于共培养的生物膜表面，但它们的丰度随着时间的推移而下降，到第5天，没有观察到eDNA，在表面上或在基质内。缺乏eDNA的铜绿假单胞菌定植的生物膜保留了其机械性能。观察结果表明，预先存在的K.hansenii生物膜支架抑制铜绿假单胞菌PAO1eDNA的产生，并表明eDNA的产生是铜绿假单胞菌对其环境粘弹性的响应。
