Biofilm formed in vitro by mycobacteria has been associated with increased antibiotic tolerance as compared with planktonic cells. Cellulose has been identified as a component of DTT-exposed biofilms formed by M. tuberculosis. The celA1 gene of M. tuberculosis encodes a cellulase, which could affect the formation of biofilm by slow-growing mycobacteria. In this work, the celA1 gene of M. tuberculosis was cloned into the integrative pMV361 plasmid and then transformed into M. bovis BCG Pasteur to produce BCG:celA1, to have celA1 expressed from the strong promoter hsp60. We compared planktonic and biofilm growth, possible presence of CelA1 in whole protein extracts, quantitated biofilm, presence of monosaccharides, and bacillary burden in lungs after aerosol infection in BALB/c mice. Differences in the appearance of the surface pellicle and of the biofilm attached to the substrate were observed. In biofilms, we observed a significant decrease of glucosamine in BCG:celA1 compared with BCG:pMV361. Finally, BCG:celA1 had lower viable bacteria than the BCG:pMV361 strain after 24 h and 3 weeks post-infection, but no difference was found at 9 weeks post-infection.

中文翻译：

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BCG 中 celA1 基因的过度表达改变了表面薄膜、生物膜中的葡萄糖胺含量，并影响体内复制

与浮游细胞相比，分枝杆菌在体外形成的生物膜与增加的抗生素耐受性有关。纤维素已被确定为由结核分枝杆菌形成的暴露于 DTT 的生物膜的组成部分。结核分枝杆菌的 celA1 基因编码一种纤维素酶，可影响生长缓慢的分枝杆菌生物膜的形成。在这项工作中，结核分枝杆菌的 celA1 基因被克隆到整合的 pMV361 质粒中，然后转化到牛分枝杆菌 BCG Pasteur 中以产生 BCG:celA1，从强启动子 hsp60 表达 celA1。我们比较了浮游生物和生物膜的生长、全蛋白提取物中可能存在的 CelA1、定量的生物膜、单糖的存在以及 BALB/c 小鼠气溶胶感染后肺部的细菌负荷。观察到表面薄膜和附着在基材上的生物膜的外观差异。在生物膜中，与 BCG:pMV361 相比，我们观察到 BCG:celA1 中的氨基葡萄糖显着减少。最后，在感染后 24 小时和 3 周后，BCG:celA1 的活菌数低于 BCG:pMV361 菌株，但在感染后 9 周时没有发现差异。