Soldavini Pelichotti P C, Martinefski M R, Boscolo O, Tripodi V P, Lucangioli S E, Trejo F M, Pérez P F
Centro de Investigación y Desarrollo en Ciencia y Tecnología de los Alimentos (CCT- La Plata CONICET, CIC-PBA, Facultad de Ciencias Exactas, UNLP), Argentina; Cátedra de Microbiología. Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, UNLP), Argentina; Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina.
Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Ciencias Químicas, Buenos Aires, Argentina; Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Departamento de Tecnología Farmacéutica, Buenos Aires, Argentina; Universidad de Buenos Aires, Buenos Aires Instituto de Tecnología Farmacéutica y Biofarmacia (InTecFyB), Facultad de Farmacia y Bioquímica, Argentina; Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina.
Microb Pathog. 2025 Feb;199:107250. doi: 10.1016/j.micpath.2024.107250. Epub 2024 Dec 21.
Clostridioides difficile is a spore-forming pathogen capable of causing severe disease in humans. Critical stages in the biological cycle of this microorganism include sporogenesis/germination and toxin production by vegetative cells. Antagonizing these pivotal events could aid in prevention and treatment to manage this pathogen. Given that bifidobacteria can impede the growth, toxin production, and in vivo effects of C. difficile, the present study aimed to determine the impact of selected strains of bifidobacteria on crucial steps of the pathogen's biological cycle. Clinical strains of C. difficile, including ALCD3, GCD2, GCD4, and the reference strain VPI 10463 (ATCC 43255), were utilized. Bifidobacteria strains comprised CIDCA 5310 and CIDCA 5317 (Bifidobacterium bifidum and Bifidobacterium adolescentis, respectively). Cocultures of bifidobacteria with C. difficile resulted in a strain-dependent inhibition of sporulation (thermoresistant forms). This effect could be partially attributed to the production of lactic acid. Co-cultivation with all three bifidobacteria downregulated the expression of the tcdB gene, whereas strains CIDCA 5310 and CIDCA 5317, but not CIDCA 531, downregulated the expression of the cspAB gene. Bifidobacteria were capable of deconjugating taurocholate, as demonstrated by the increase in cholic acid concentration. Remarkably, strain CIDCA 531 almost entirely reduced taurocholate concentration. This ability correlated with the inhibitory effect on germination of spent culture supernatants of bifidobacterial cultures grown in medium containing taurocholate. Our results demonstrate that bifidobacteria can modify the biological cycle of C. difficile by altering the efficiency of sporulation and germination. Additionally, co-cultivation with bifidobacteria modulates the expression of genes associated with toxins and critical events in sporogenesis. These findings are significant for understanding the underlying mechanisms of the probiotic effect of bifidobacteria in the context of C. difficile infections.
艰难梭菌是一种能够在人类中引起严重疾病的产芽孢病原体。这种微生物生物周期中的关键阶段包括孢子形成/萌发以及营养细胞产生毒素。对抗这些关键事件有助于预防和治疗该病原体。鉴于双歧杆菌可阻碍艰难梭菌的生长、毒素产生及体内效应，本研究旨在确定所选双歧杆菌菌株对该病原体生物周期关键步骤的影响。使用了艰难梭菌的临床菌株，包括ALCD3、GCD2、GCD4以及参考菌株VPI 10463（ATCC 43255）。双歧杆菌菌株包括CIDCA 5310和CIDCA 5317（分别为双歧双歧杆菌和青春双歧杆菌）。双歧杆菌与艰难梭菌的共培养导致了孢子形成（耐热形式）的菌株依赖性抑制。这种效应可能部分归因于乳酸的产生。与所有三种双歧杆菌共培养下调了tcdB基因的表达，而菌株CIDCA 5310和CIDCA 5317（而非CIDCA 531）下调了cspAB基因的表达。双歧杆菌能够使牛磺胆酸盐去结合，胆酸浓度的增加证明了这一点。值得注意的是，菌株CIDCA 531几乎完全降低了牛磺胆酸盐浓度。这种能力与对在含牛磺胆酸盐培养基中生长的双歧杆菌培养物的陈旧培养上清液萌发的抑制作用相关。我们的结果表明，双歧杆菌可通过改变孢子形成和萌发效率来改变艰难梭菌的生物周期。此外，与双歧杆菌共培养可调节与毒素及孢子形成关键事件相关基因的表达。这些发现对于理解双歧杆菌在艰难梭菌感染背景下益生菌作用的潜在机制具有重要意义。
