背景:本研究的目的是比较葡萄糖和甘油(作为主要可发酵补充剂提供)对粪肠球菌根管来源菌株和其他环境菌株的碱性耐受性和生物膜形成能力的影响。
方法:当在微量滴定板中提供pH水平为8和11的葡萄糖和甘油时,比较粪肠球菌分离物(通过16S核糖体DNA测序鉴定)的浮游生长动力学和生物膜形成能力。在随后调节至pH水平11后,测量在中性pH水平(供应有葡萄糖或甘油)下形成的生物膜板的代谢活性。
结果:检查了10个分离株(7个来自根管,3个来自其他来源)。无论可发酵补充物(葡萄糖或甘油)或分离物的来源如何,在升高的碱度下,滞后期和倍增时间都会增加。生物膜的形成和代谢活性因菌株而异,但两者都与隔离的来源有关。总的来说,与甘油相比,在葡萄糖中生长时,在pH为8时与pH为11时相比,生物膜的形成得到了增强(与可发酵补充剂无关)。与葡萄糖相比,甘油的供应并未增加浮游生长速率或生物膜发育,但显着增加了生物膜的代谢活性,特别是在pH为11的情况下,而pH为8。
结论:在坏死或充满根管的营养剥夺环境中,甘油可以是在碱性处理条件下促进粪肠球菌代谢活性增加的替代能源。
BACKGROUND: The aim of this
study was to compare the effects of glucose and glycerol (provided as principal fermentable supplements) on alkaline tolerance and biofilm-forming capabilities of root canal-derived strains of Enterococcus faecalis and those from other environments.
METHODS: The planktonic growth kinetics and the biofilm-forming capabilities of E. faecalis isolates (identified by 16S ribosomal DNA sequencing) were compared when supplied with glucose and glycerol at pH levels of 8 and 11 in a microtiter plate. The metabolic activity of the biofilms plate that formed at a neutral pH level (supplied with either glucose or glycerol) was measured after subsequent adjustment to a pH level of 11.
RESULTS: Ten isolates (7 from root canals and 3 from other sources) were examined. The lag phase and the doubling time increased under elevated alkalinity irrespective of either the fermentable supplement (glucose or glycerol) or the origin of the isolate. Biofilm formation and metabolic activity varied among strains, but neither was related to the source of isolation. In general, biofilm formation was enhanced when grown in glucose compared with glycerol and at a pH of 8 compared with a pH of 11 (irrespective of the fermentable supplement). The provision of glycerol did not increase either the planktonic growth rate or biofilm development compared with glucose but significantly increased the metabolic activity of biofilms, especially at a pH of 11 compared with a pH of 8.
CONCLUSIONS: In the nutrient-deprived environment of a necrotic or root-filled root canal, glycerol may be an alternative energy source that can promote increased metabolic activity of E. faecalis under alkaline treatment conditions.