Fundamental and Applied Research for Animals & Health (FARAH), Faculté de Médecine Vétérinaire, Département des Sciences des Denrées alimentaires, Université de Liège, Avenue de Cureghem 10, 4000 Liège, Belgique.
Instituto de Investigación Biomédica de Málaga-IBIMA. Málaga, Spain. Unidad de Gestión Clínica de Aparato Digestivo, Hospital Universitario Virgen de la Victoria, Málaga, 29590, Spain.
FEMS Microbiol Lett. 2022 Oct 29;369(1). doi: 10.1093/femsle/fnac087.
Clostridioides difficile is a spore-forming anaerobic Gram-positive bacterium responsible for a broad spectrum of intestinal symptoms and healthcare-associated diarrhoea. The hypothesis of this work was that different in vitro conditions, notably pH and human faecal microbiota composition, impact the germination and/or the growth of C. difficile. This study aimed to correlate growth kinetics of the bacterium with these two physiochemical parameters by using a static in vitro model. To better understand the initial gut colonisation, several growth curve assays were carried out to monitor the behaviour of the spores and vegetative forms of C. difficile strain 078 under different conditions mimicking the gut environment. When the faeces were added, no spore germination or growth was observed, but C. difficile spores germinated in vitro when the pH was maintained between 6.6 and 6.9 for four different faeces donors. The evolution of microbiota studied by 16S rDNA profiling showed high proportions of Enterobacteriaceae and E. coli/Shigella when C. difficile grew, regardless of the inoculated faeces. This model helped us to understand that the germination and growth of C. difficile are strongly pH dependent, and further research is needed to evaluate the potential impact of the gut microbiota composition on C. difficile.
艰难梭菌是一种产芽孢的厌氧革兰氏阳性细菌，可引起广泛的肠道症状和与医疗保健相关的腹泻。这项工作的假设是，不同的体外条件，特别是 pH 值和人类粪便微生物群组成，会影响艰难梭菌的发芽和/或生长。本研究旨在通过使用静态体外模型，将细菌的生长动力学与这两个生理化学参数相关联。为了更好地了解初始肠道定植，进行了多次生长曲线测定，以监测在模拟肠道环境的不同条件下，艰难梭菌 078 株的孢子和营养体形式的行为。当添加粪便时，没有观察到孢子发芽或生长，但当 pH 值在 6.6 和 6.9 之间维持 4 个不同粪便供体时，艰难梭菌孢子在体外发芽。通过 16S rDNA 分析研究的微生物群进化显示，无论接种的粪便如何，当艰难梭菌生长时，肠杆菌科和大肠杆菌/志贺菌的比例都很高。该模型帮助我们了解到，艰难梭菌的发芽和生长强烈依赖于 pH 值，需要进一步研究以评估肠道微生物群组成对艰难梭菌的潜在影响。
