A modified chemostat system to study the ecology of oral biofilms
A modified chemostat system to study the ecology of oral biofilms
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DOI：
10.1111/j.1365-2672.1996.tb03199.x
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发表时间：
1996-02-01
期刊：
影响因子：
--
通讯作者：
Cummins, D
中科院分区：
文献类型：
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作者：
Bradshaw, DJ;Marsh, PD;Cummins, D
此前，我们开发了一种恒化器系统来研究多达 10 种口腔细菌群落的行为和特性。本研究描述了对该系统的修改，以纳入可移动和可更换的羟基磷灰石（人类牙釉质中的主要矿物质）盘，生物膜可以在该盘上形成。将羟基磷灰石盘浸入恒化器中已知的时间段，并通过活菌计数确定生物膜的细菌含量。初始沉积速率很快，1 小时后即可检测到所有 10 个物种，并且生物膜中的细菌数量持续增加 21 d。生物膜的物种组成反映了周围流体相的物种组成，并且仅显示出在体内牙菌斑形成过程中观察到的“物种演替”类型的有限迹象，尽管旧生物膜中厌氧物种的比例有所增加。四天的生物膜显示出最小的变异性，并被选为“标准生物膜”以进行更详细的研究。 4 d 生物膜细菌组成的变异性在单次恒化器运行内和独立恒化器运行之间具有可比性。在没有 pH 控制的情况下进行葡萄糖脉冲会导致致龋物种的选择；生物膜群落的破坏不如同等浮游培养物明显。该模型系统在研究各种因素对生物膜形成的影响以及比较抗菌系统对生物膜的功效方面具有相当大的潜力。
Previously, we developed a chemostat system to study the behaviour and properties of a community of up to 10 species of oral bacteria. The present study describes modification of this system to incorporate removable and replaceable hydroxyapatite (the major mineral in human dental enamel) disks on which biofilms could develop. Hydroxyapatite disks were immersed in the chemostat for known time periods, and the bacterial content of biofilms determined by viable counting. Initial deposition rates were rapid, with all 10 species detected after 1 h, and the numbers of bacteria in biofilms continued to increase for 21 d. The species composition of biofilms reflected that of the surrounding fluid phase, and showed only limited signs of the type of 'species succession' which is observed in developing dental plaque in vivo, although anaerobic species increased in proportion in older biofilms. Four-day biofilms showed the least variability and were chosen as the 'standard biofilm' for more detailed study. Variability in the bacterial composition of 4-d biofilms was comparable both within a single chemostat run and between independent chemostat runs. Glucose pulsing in the absence of pH control resulted in the selection of cariogenic species; the disruption of the biofilm community was less marked than that of the equivalent planktonic culture. The model system has considerable potential in studying the effects of a variety of factors on biofilm development, as well as in comparing the efficacy of antimicrobial systems against biofilms.